This is a DRAFT of a book about building in highway airspace, i.e., a freeway cap, also known as a highway cap, or deck, or lid. The book also applies to other freeway right of way projects like parks under freeway viaducts. Please help me finish by commenting suggestions and corrections on the individual chapters. Thank you! (you may see your name in the final product).Continue Reading Book: How to Build a Freeway Cap
This is not a book about construction methods. Rather this is a book about how to accomplish that rarest of feats: Restoring the land occupied by wide, noisy, polluted highways to land usable for parks and buildings. It’s about mending divided communities are mended, mitigating noise and air pollution, and making open space. While rare, these projects are not unprecedented. Moreover, they are becoming increasingly popular, particularly as urban and transit oriented living has seen a resurgence.
The projects over highways are referred to as, among other things, freeway or highway “caps,” “decks,” and “lids.” For convenience, this book will use the term “freeway cap” or just “cap” when referring to these highway airspace projects.
However, these aren’t the only such projects. Some involve reclaiming the space underneath overpasses, or removing the offending highway altogether. Nevertheless, they involve building in a right of way controlled by federal and state departments of transportation, and thus involve many of the same issues.
Accordingly, this is a book about planning, about obtaining public, regulatory, and agency approvals; and about funding projects in highway airspace. “‘Air rights’ or ‘airspace’ are terms used in highway terminology to describe that area above or below the plane of the transportation facility and located within the right-of-way boundaries.” This book will have a special but not exclusive focus on highways that received federal funding when built. These highways have unique process issues and limitations.
My own interest in the topic came from my daily commute into the city, which included crossing over the Interstate 5 trench that separates downtown San Diego from its magnificent Balboa Park. Because it is already in a trench, it seems feasible to cover it and put a park or development on top of it – to essentially make the strip mine of cars disappear. Practically any use would be better than what it is now. I was far from the first to consider this possibility, and the City’s plans already identified capping the freeway as a goal. This project has yet to be realized, but a group of us now regularly meet to give the plan momentum.
Across the country, proponents of plans and projects to build parks and other facilities in highway airspace have expended countless hours researching, planning, lobbying, and fundraising to bring their projects to fruition. Their efforts are fueled by love of community rather than profit. In that spirit, they have been incredibly generous in sharing the lessons and shortening the learning curve for the next project. This book is largely a compilation of their excellent efforts.
 U.S. Dept. of Transportation, Federal Highway Administration, Airspace Guidelines to 23 CFR 710.405 – 710.407 (Revised August 10, 2010)
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The Federal Aid Highway Act of 1956 caused a major expansion of our highways, creating the system as we know it today. The 1956 Act had several predecessors, but none approached its scope or ambition, which has continued to the present. The Act had many benefits in terms of improving transportation, the economy, national security, and housing options. However, in combination with the Country’s housing policies, the Act also did tremendous damage to cities and countryside alike.
In cities around the country, the Act ushered in highways, expressways, and freeways that damaged and divided communities, dislocated people and took their homes, and emitted toxic pollution in dense residential areas. The Act severely damaged the lives of those who were dislocated from their homes or were forced to live adjacent to these rivers of air pollution, noise, and blight. Existing neighborhoods and their residents were sacrificed for the benefit of new outer suburban neighborhoods. This pattern took place during the era of “white flight.” Thus, downtowns and urban neighborhoods were abandoned along class and racial lines. To add insult to injury, those who abandoned the urban core demanded the physical destruction of large swaths of the neighborhoods of the people they left behind in order to facilitate their long commutes to and from their new far flung suburban homes. While perhaps worst in the U.S., the damaging impacts of freeways was not unique to the U.S.
The after-effects of this over-emphasis on highways and auto-mobile transportation is:
- Divided neighborhoods
- Scarred urban and rural landscapes
- Removal of public transit as a viable transportation alternative for the majority of the population
- Increased air pollution
- Sprawled development patterns and associated infrastructure costs
- Aggravated poverty and decreased economic opportunities for people left behind in the outward migration
Jane Jacobs’s seminal work, The Death and Life of Great American Cities, is one of the most widely read books about urban form. Jacobs activism started when she opposed the dissection of a New York City park (Washington Square Park) by a planned roadway near her Greenwich Village home in the late 1950s. The roadway through the park was part of an urban renewal and roadway program lead by Robert Moses. Moses had many accomplishments and was respected for his intelligence, ability, and integrity. He wanted cities that exuded light, open space, parks, and which were easily navigated. He wanted people who lived in slums to have better living conditions. Some saw him as the Baron von Haussman of New York.
However, Moses now is known more for his nemesis role in Jacobs life and authorship. He is associated with the evisceration of cities and neighborhoods to build highways and expressways (and “the projects,” i.e. low income housing which replaced the slums). Some attribute to him racism and disdain for the poor. Despite the renown of Jacob’s 1960 book, Moses auto-centric vision for U.S. cities remained dominant for decades, and arguably still does.
While wholesale removal or mitigation of neighborhood-dissecting highways is likely decades off, if ever, it is now widely recognized that these highways detract from the livability of the adjacent neighborhoods. Nevertheless, a ground swell has been building. The groundswell is comprised mostly of grassroot community efforts seeking to mitigate or cover up the scars and barriers created by urban highways, and to create open space for park starved urban neighborhoods. These efforts seek to repurpose all or a portion of the highway right-of-way. Few at first, these efforts have blossomed into numerous projects across the country. They can include, among other things: covering highways with parks or buildings, converting the space beneath viaducts and ramps into parks, and converting expressways into landscaped boulevards. Now, cities and communities are beginning to reconnect neighborhoods and heal the wounds caused by urban highways.
Freeway caps and other “healing” projects have other benefits too. Benefits to the surrounding communities include:
- Increased property values
- Increased density and housing
- Increased retail sales
- Increased hotel development and occupancy
- Increased area jobs
- Increased property tax, payroll tax, hotel tax, and sales tax revenue
- Improved park and recreational opportunities
- Improved air quality
Freeway cap proposals are still met with skepticism. However, their increasing number is breeding increasing understanding at all levels of government. Yet they are highly complex projects that are still in their infancy in terms of number of projects actually built. Regulations and regulatory agencies still insert unnecessary obstacles for their planning, approval, and construction. Construction techniques are still being pioneered. And of course, funding is difficult and complex. This book seeks to aid those contemplating such a project, and to serve as a reference manual.
 Baron von Haussman is both lauded and panned for the wide boulevards of Paris.
 Campanella, Thomas J., How Low Did He Go?, CityLab (Atlantic Magazine – July 9, 2017), retrieved from https://www.citylab.com/transportation/2017/07/how-low-did-he-go/533019/
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2. What’s Been and Being Done Elsewhere
Broadly speaking, there have been many projects built in highway airspace during the past half century. Mini-storage and telecommunications facilities built in highway airspace are relatively common. However, this book is about projects that knit together the torn fabric of cities by creating land in highway airspace for parks and buildings. Never before have there been as many proposed freeway caps and other freeway right-of-way projects as there are presently. Some of the more notable projects, including already-built, under construction, and planned projects, include the following:
Freeway Park, Seattle
Built in 1973, Seattle’s Freeway Park is sometimes referred to as the first public park built on a freeway cap. It was recently featured in PBS’s 10 Parks that changed America. The show featured 10 parks deemed by the show’s producers as the most influential in the U.S. The Freeway Park cap was designed by the renowned modernist landscape architecture firm Lawrence Halprin & Associates, whose projects include the FDR Memorial Park in Washington D.C. and Lovejoy Plaza in Portland, OR. Freeway Park is characterized by its multi-level plazas and modernist / brutalist concrete water features that mimic the landscape of the NorthWest. The park spans I-5 in downtown Seattle over a curved part of the freeway with ramps and multiple levels. In the 1990s and early 2000s, it became blighted and crime ridden. However, with help from the Project for Public Spaces, the city implemented measures which appear to have alleviated the blight and which make the park hospitable again. Further renovations that would preserve Halprin’s design are underway.[i]
Klyde Warren Park, Dallas Texas
(by James Burnett, its designer)
Klyde Warren Park is Dallas’ central urban park that has literally and figuratively bridged the city’s downtown cultural district with the neighborhoods to the north. The vibrant, 5.2 acre deck park brings Dallas-Fort Worth citizens together with free activities and amenities, including concerts, lectures and fitness classes. The park bridges over the 8-lane Woodall Rodgers Freeway, which had been a barrier between Downtown and Uptown. Dallas leaders formed a non-profit foundation, which was responsible for operations and maintenance of the park. Built with a combination of public and private funds, the park features a flexible, pedestrian-oriented design, children’s park, great lawn, restaurant, performance pavilion, fountain plaza, games area, dog park and botanical garden.
The park has had a major impact on the community, featuring a multitude of activities that connect Dallasites together while improving the quality of life. The park has also contributed significantly to the economic development of the surrounding urban core, increasing activity for neighboring businesses and cultural institutions and increasing property values. All of this development spurred by the park will contribute to a projected 8.8% population increase in the two Census Block Groups surrounding the park by 2017, supporting the regional goal of making metropolitan centers attractive and viable places to live. In addition to impacting real estate and property values, the park has provided several other economic benefits, including park operations and maintenance savings through sustainable design and the implementation of green technologies.
Rose Fitzgerald Kennedy Greenway, Boston MA.
Known as the Big Dig during construction, the project had an inauspicious start. Construction was plagued by corruption, design flaws, substandard materials, accidents and even a death. It is often referred to as the most expensive highway project in U.S. History. Construction commenced in 1991 and was completed in 2007. It cost nearly $15 billion, although some estimates have it as high as $22 billion or more – most of it federal funding.
Despite the steep cost in both money and blood, it may also be the country’s most successful highway cap project. It spurred development and completed the city’s famed Emerald Necklace park system, originally conceived and designed by Frederick Olmstead. Among other things, the project lowered the elevated John F. Fitzgerald Kennedy Expressway (I-93) into a tunnel beneath a greenway. Prior to the project, I-93 went through the heart of Boston and its waterfront. However, the scope of the project was much broader. It sought to solve much of central Boston’s transportation flow problems in one master stroke by re-aligning, re-routing, re-ramping, and tunneling a new route (I-90) under the harbor.
The project has greatly reduced traffic congestion and travel time, and it has facilitated an increase in property values and redevelopment along the greenway that was formerly the expressway – now renamed the Rose Fitzgerald Kennedy Greenway.
Teralta Neighborhood Park, I-15, San Diego
It started like a latter day Robert Moses project: a major freeway extension through densely populated urban San Diego neighborhoods. However, this was the early 1980s rather than the 1960s. Residents vigorously fought the I-15 extension through San Diego’s Mid-City neighborhoods. Unfortunately, freeway expansions in California have always been, and continue to be, nearly unstoppable. The I-15 extension resulted in the demolition of hundreds of homes and the displacement of thousands of residents.
Nevertheless, the impacted neighborhoods had their own Jane Jacobses who attained several precedent setting concessions. The most important concession was a five acre park built on top of the freeway named Teralta Park. The park now hosts concerts, picnicking, children’s play areas, and an expansive grass area that can be used for recreation. Another concession included a second smaller freeway cap with space for businesses (to partially replace some of the businesses lost to the freeway). It was designed to accommodate a dedicated mass transit line. Additionally, the uncovered part of the freeway was designed to facilitate future covering as well as to contain freeway exhaust. Recently, Bus Rapid Transit stations have been built in the freeway center, in accordance with the community’s plans.
Presidio Parkway, San Francisco CA
The recently completed Presidio Parkway project consists of two freeway cap parks built over a four lane divided freeway (i.e., “parkway”). The project was originally envisioned as a freeway expansion / replacement project to improve traffic capacity, seismic stability, and driving safety on the portion of State Route 101 that feeds into the Golden Gate Bridge and connected San Francisco with Marin. However, that section of SR-101 runs through the Presidio National Park and one of the most scenic and iconic areas in the country. The caps were built to reconnect the main portion of the park with the Bay. Design and construction of the project involved the first use of a public private partnership to finance the project (described in more detail in Chapter 3).
Doyle Dr. / SR-101 before Presidio Parkway project (Sept. 2008 Google Earth)
Presidio Parkway upon completion – notice the two areas where the park extends over SR-101. (U.S.D.O.T. schematic photo)
Capitol Crossing, Washington DC.
The Capitol Crossing project in Washington DC is currently under construction and will span 3 blocks of I-395. It comprises 2.2 million square feet of development on a 7 acre site. It is a privately funded $1.3 billion project. It is precedent setting for several reasons. To date, most highway caps have used public funding to create either public park space or publicly owned facilities like convention centers. In contrast, Capital Crossing is a privately funded development consisting of commercial and residential buildings (including affordable units). Another unique aspect of the project is that it will construct four levels of below grade parking. The project also pioneers new ground on environmental fronts.This cap will utilize “eco-chimneys” to vent and filter emissions from below. These filters will result in a net reduction of fine particulate air pollution. Additionally, the development will utilize “cogeneration” from traffic in the tunnel to produce heat and electricity. The project concept dates to 1989, when then-Mayor Marion Barry awarded rights to develop I-395 to the Washington Development Group, who were succeeded by the Louis Dreyfus Property Group. Property Group Partners (PGP) acquired the development rights in 2006. PGP started construction in 2014.
Unlike other highways, the City owned this section of I-395, which was on an easement. As a result, the airspace was not subject to the regulations which make private development nearly impossible on other freeways (discussed later in this book). Accordingly, the City was able to sell the airspace for private development.
Capitol Crossing rendering courtesy of Property Group Partners
Hollywood Central Park, Los Angeles CA
At nearly 1 mile in length and 38 acres in area, Hollywood Central Park will be – upon completion – the longest freeway cap project in the country. While still a planned project rather than a built or under-construction project, Hollywood Central Park is well advanced, both in planning and fundraising. At the time of this writing, the project is entering environmental review. Hollywood Central Park, along with the Klyde Warren Park in Dallas, are probably the best examples of retrofit caps spearheaded by local communities and dedicated to open space. In the case of HCP, the vision began with architect Edward V. Hunt nearly 30 years ago, and was later revived by the Hollywood Chamber of Commerce. As with Klyde Warren, a non-profit organization was formed – Friends of Hollywood Central Park (FHCP) – to become the primary advocate and fundraiser for the park. In particular, former Chamber member Laurie Goldman dedicated her considerable talents to marshalling the deep resources of Hollywood, putting together an expert board, and overcoming regulatory and political hurdles to bringing the park cap much closer to reality. FHCP maintains an excellent website chronicling the project.
Chicano Park, Barrio Logan San Diego CA
Designated a National Monument in 2017, Chicano Park in San Diego’s Barrio Logan is not a freeway cap park. Rather, it is a park located on land and airspace underneath freeway overpasses and ramps at the juncture of Interstate 5 and San Diego’s Coronado Bridge (over the City’s harbor). Thus, it is in the freeway right-of-way airspace just like a freeway cap over a freeway. Accordingly, the regulatory and agency processes are nearly the same as a freeway cap.
One of the park’s most distinguishing features are murals depicting the Mexican-American (aka Chicano) experience and Barrio Logan’s history. The park arose from a grassroots resistance movement sparked by the destruction and displacement caused by freeway construction. Like many diverse working class urban neighborhoods across the country, Barrio Logan was selected for the routing of I-5 and the construction of the Coronado Bridge rather than wealthier or whiter neighborhoods. Barrio Logan, an ethnically Chicano enclave, had withstood decades of discriminatory assaults. In the face of such discrimination, the neighborhood had built-up self-sufficiency, resourcefulness, solidarity, and pride. Although unable to stop the freeway and bridge routing (built in 1963 and 1969 respectively), the space underneath the freeway and bridge ramps became the focal point of community activism toward recovering the land for a neighborhood park. The state had other plans, including the construction of a California Highway Patrol Station. In response, community activists occupied the park and began converting it into a public park, landscaping it and painting murals on the overpass support structures – all without permission or permits. The murals told the history and struggles of the Chicano movement. In 1970, the activists succeeded in getting the state to cancel the CHP station and accept the park. In 1980, the City of San Diego designated the park a historic landmark. In 1987, the City designated the murals as public art. In 2013, the park was listed on the National Register of Historic places, and 2017 it was named a National Historic Landmark. It is part of a small subset of the approximately 2,500 U.S. National Historic Landmarks that celebrate the culture and history of minority groups.
 PBS (2016), 10 Parks that changed America, Retrieved from: http://www.pbs.org/program/ten-that-changed-america/10-parks-changed-america/ (The show was part of a series entitled 10 that changed America and included an episode on 10 homes, 10 buildings, 10 towns, and 10 parks.)
 Wachs, A., (April 10, 2018), Preservation-minded renovation of Halprin’s Freeway Park moves forward, The Architects Newspaper, Retrieved on May 1, 2018.
 See also Presdio Parkway Press Center for more images at http://www.presidioparkway.org/press_center/photos/
 According to the Capitol Crossing Developers, Property Group Partners, Eco-Chimneys cost approx. $50 million and were required by FHWA as part of a new policy. FHWA added enormous cost and time to the project by redundant engineering and design. Capitol Crossing did not involve an airspace lease. In an unusual circumstance, the city owned the land underneath, and in turn, the air rights above, the highway (I-395). FHWA had an easement for the highway. This not the usual circumstance, where the highway land has been acquired by eminent domain. Conversation with David A. Happ, Senior Vice President Leasing and Operations, PGP Partners.
 Skidmore, Owings, & Merrill, LLP, Capitol Crossing, SOM website description of project retrieved from: http://www.som.com/projects/capitol_crossing
 Neibauer, Richard (March 27, 2012), I-395 air rights project now Capitol Crossing, Washington Business Journal, retrieved from: http://www.bizjournals.com/washington/blog/2012/03/i-395-air-rights-now-capitol-crossing.html
 Hollywood Central Park website. Retrieved January 15, 2017 from http://hollywoodcentralpark.org/
 Torero, M., Beltran, B., Adams, W. (Nov. 1, 2016). Barrio Logan vs the Stadium: Why it Matters. UrbDeZine. Retrieved from https://sandiego.urbdezine.com/2016/10/29/barrio-logan-vs-stadium-matters/
 Chicano Park. (n.d.). In Wikipedia. Retrieved September 14, 2017 from https://en.wikipedia.org/wiki/Chicano_Park
 Warth, G. (Jan. 11, 2017). Chicano Park named National Historic Landmark. San Diego Union Tribune. Retrieved from: http://www.sandiegouniontribune.com/news/politics/sd-me-chicano-historic-20170111-story.html
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3. Planning Considerations for a Highway Airspace Project
Needless to say, a freeway cap project starts with planning. Planning a freeway cap starts with the idea and a motivated person or group, and, preferably, community outreach. Bringing a freeway cap project to will be a mult-year, if not multi-decade, effort. Putting together a sustainable vision, plan, and organization is critical to ultimate success.
Establish Project Goals and Vision:
An early step in the planning process is to establish project goals. The project goals will help to shape a vision that is resilient. Project goals should relate to both new opportunities and the preservation of existing community assets and benefits. It can be a useful strategy to try to make the project part of the solution to as many community goals as possible. Typical goals include:
- Reconnect neighborhoods divided by the highway / freeway;
- Create new open space or extend existing open space;
- Create recreational facilities;
- Preserve / restore urban street grid;
- Preserve view corridors;
- Create active transportation (walking, bicycling) corridors;
- Mitigate / reduce air pollution from auto emissions;
- Mitigate stormwater runoff;
- Create parking reservoir;
- Create new developable space;
- Utilize freeway cap to provide space and infrastructure for important public facilities, including but not limited to, transit facilities, conference space, and cultural facilities.
Seek Synergy Opportunities
It may also be useful to seek out other planning and transportation initiatives for synergy, coordination, and cross-use. Making the project multi-use and multi-purpose may lead to additional support and funding opportunities. This strategy will require maintaining some flexibility early in the process. For example, in our San Diego effort, many people and groups who were connected with Balboa Park and Downtown felt there was a need for more parking, particularly for the park. There were also multiple efforts underway to create transit connections, including a gondola project initiative and two streetcar project initiatives. These circumstances created potential opportunities for a transit station and for additional parking resources for the park, which in turn created potential for the related infrastructure funding to build shared highway cap infrastructure. The same is true of the the Ventura Beach + Town project.
Plug into Planning Documents and Capital Expenditure Programs
Being part of formal planning documents is an important step toward securing funding. For example, San Diego’s Downtown Community Plan contained several references to a highway cap, such as:
“To restore downtown’s historic connection to Balboa Park, the Community Plan proposes a green lid over I-5 to integrate them, along with a new connector at 8th Avenue.”
This inclusion in the Downtown’s central planning document in turn placed it in the City’s Development Impact Fee budget (below).
Additionally, most cities have some sort of capital improvement project list and prioritization program (CIP). Getting the project into a formal planning document is usually a prerequisite to getting on the CIP.
Research future right of way plans
A critical piece of information for any highway air space plan is to determine potential conflicting plans for the right of way. Most obviously, highway expansion and reconfiguration plans must be determined. It is important to check with all potential agencies, not simply the state’s DOT. Check with regional and local planning agencies. Even when there are expansion plans for a right of way, a freeway cap project may still be feasible by designing the cap to accommodate the expansion. Additionally, check to determine whether existing bridges within the project boundaries are scheduled for upgrades or replacement, or whether they satisfy current bridge construction requirements. If a bridge within the project boundaries is structurally or otherwise deficient, this fact may have implications for the cap project. It may also create an opportunity for synergy if a case can be made to the SDOT to accelerate bridge replacement or upgrades.
Additionally, nearby railway right of ways may impact the ability to cap a highway, including rail right of ways that cross over the relevant highway. Railways not only reserve the right to use certain land for their trains, but also limit rail crossings
Engage Community, Elected Officials, and Agency Chiefs
Public outreach and participation by all “stakeholders” is critical, not only to gain support but also to create a project that reflects the priorities of the community.
Residents and community groups near proposed freeway cap are the most important participants. They will be most directly effected by the freeway cap and should have the most prominent role in designing it. Gaining the support of adjacent communities, and neutralizing opposition, is a prerequisite to ultimate success.
In reaching out to residents and community organizations, create a Powerpoint slide presentation or renderings. Include examples of other cap projects. Include documentation of helpful planning documents. Schedule presentations to local community groups and business groups. Consider hosting a workshop with a broad spectrum of invitees. Solicit and record their goals and ideas, and incorporate them into the design.
Cap project proponents should make the regional DOT head one of the first officials with whom to get an audience. The DOT will figure prominently in most such projects. This will be an opportunity to assess the agency’s attitude toward cap projects in general and the proposed project in particular. More importantly, proponents can learn of conflicting or synergistic plans, regulations, and initiatives. It may be an opportunity to establish a positive and cooperative relationship, or at least mitigate a hostile one.
Ask for meetings with elected officials and their staff. This strategy includes local, state, and federal officials. These unique projects typically benefit from support at all levels. As with any major project, mayors and city council members are needed for approval and funding. State officials may be important for expedited environmental review, regulatory relief, and funding. The support of federal officials may be needed for similar reasons. It is not necessary to gain support of the project at the early stages. Simply getting on the elected officials’ radars can be helpful in learning about conflicting initiatives or synergistic opportunities. Additionally, these meetings are an opportunity to educate the official feasibility and usefulness of a cap project, and to overcome preconceived prejudices regarding their feasibility or usefulness. The Friends of Hollywood Central Park puts together annual trips to Washington D.C. to meet with federal officials.
Environmental, social justice, architecture and urban planning, and arts organizations can all be important allies or difficult adversaries.
Create a Positive Public Image
As part of the overall campaign, the title and visual image of the project can be a powerful aid. The branding should quickly and intuitively convey the most important benefit of the project. It should create a positive first impression. Branding includes the title and logo used for the project. For example, in the City of Ventura, the city and project design team changed the title of its planned freeway cap project from The U.S.-101 Freeway Capping Project to The Ventura Beach + Town project. They wanted to convey the ultimate goal of the project: reunifying its downtown to the beach. The two are separated by Highway 101. The former title merely conveyed the means of doing so without communicating any benefits of the project. In contrast, the current title seeks to convey the positive vision.
Consider Adaptive Re-use Opportunities
In the Ventura project, the design team determined that certain exit and entry ramps were not needed. After looking at the cost of removal of the ramps, they considered adaptive re-use alternatives. They came up with a plan to use ramps as linear parks and pedestrian passages to parking and other project development. The most famous recent adaptive reuse project is the Highline Park in New York City. It’s not noteworthy as a highway cap project (because it wasn’t). Rather, it involved abandoned rail infrastructure that was reused as a landscaped pedestrian parkway.
Identify or Create Non-profit Entity and Board to Lead Project Planning
The Klyde Warren Park had (and has) The Woodall Rodgers Park Foundation. The Hollywood Central Park project has the Friends of Hollywood Central Park. My city’s own effort has the Balboa Park Conservancy. A non-profit organization, most likely a 501(c)(3) foundation or corporation, can be very useful in several ways. It can receive tax deductible charitable donations. It can utilize volunteers and interns without violating labor laws. It can form a board of directors with critical experience and connections, who also help to guide and sustain the effort. With adequate funding, it can apply dedicated staff to the project. It can contract with consultants and other service providers. When the project is completed, it can act as the entity which maintains, operates, programs, and fundraises for the freeway cap.
Identify Project Lead Developer
“[A] ‘Lead Agency’ is the public agency that has the primary responsibility for approving a project that may have a significant impact upon the environment.” A lead agency is thus not synonymous with project proponent. However, a lead agency can also be the lead proponent or lead developer. In any case, it is important to identify who will be the lead agency. In some cities Planning efforts can then be tailored to gaining the cooperation and approval to the lead agency. The lead agency for the project may be the State’s Department of Transportation or a municipality or county government. DOTs are most often the lead agency when the highway cap is part of the construction or expansion of an existing highway. In contrast, local governments are more likely be the lead agency in a retrofit highway cap. Delineation of responsibilities with other agencies should be set forth in a memorandum of understanding between the agencies, and any private developers.
Joint Powers Authority
In some states, two or more governmental agencies can create a distinct agency for a special purpose. Accordingly, a joint powers authority can be created for the purpose of designing and building a freeway cap structure. Such a Joint Powers Authority can have all the powers of the respective member agencies but their powers are limited by the authorizing agreement. JPA’s are distinct from their member agencies and have their own governing boards. They are particularly prevalent in California where there are approximately 1,800 JPAs, because they are expressly authorized by statute. They can enter into contracts on their own behalf and have the advantage of shielding the member agencies from liabilities and obligations incurred by the JPA. They can also formalize a commitment to the project from agencies important to the project, as well as lend the powers of those agencies necessary to accomplish the project.
As discussed in more depth in the chapter on private development, at present, a private developer of the freeway cap “backbone” infrastructure is unlikely due to the USDOT regulatory requirement that right of way (ROW) leases “[e]stablish terms for revocation of the ROW use agreement and removal of improvements at no cost to the FHWA.” However, there have been at least a couple of exceptions. First, the Presidio Parkway project involved a public-private partnership in which a private for-profit concessionaire was the lead developer of the project.
Additionally, the Capitol Crossing project described at the beginning of the book was able to be built by a private developer because the FHWA did not own the right but merely had an easement over the property, which was owned by the City. The City, in turn, sold the property to a private developer.
The ROW revocation requirements notwithstanding, there may yet be opportunities for private development outside of the ROW but adjacent or contiguous with the ROW cap infrastructure as part of an infrastructure district or other integrated planned development.
In the wake of the 2008 recession and the country’s transportation infrastructure repair and modernize backlog, there has been a push for more public-private partnerships (P3) as a means to finance and build transportation infrastructure projects. The USDOT and state agencies responded by adopting a new emphasis on creative ways to fund infrastructure, including P3s. The USDOT’s Build America Bureau (“Bureau”) and its Build America Transportation Investment Center (BATIC) exemplifies this new emphasis. The Burea’s website states its purpose as:
The Bureau streamlines credit opportunities and grants and provides access to the credit and grant programs with more speed and transparency, while also providing technical assistance and encouraging innovative best practices in project planning, financing, delivery, and monitoring.
The Presidio Parkway in San Francisco was California’s first (and thus far only) major transportation project built by a P3. It prominently features two freeway cap parks extending the Presidio National Park toward San Francisco Bay. The freeway caps were part of a project to replace Doyle Drive, a section of Hwy 101 built in 1936 connecting San Francisco and Marin via the Golden Gate Bridge. The project replaced Doyle Drive, a 4 lane roadway without center median with a six lane median separated parkway. The project was constructed in two phases. The first was accomplished via the traditional Design-Bid-Build process (DBB). The second phase was also considered for DBB, as well as for two P3 models: The Design-Bid-Finance (DBF) and the Design-Bid-Build-Finance-Operate-Maintain model (DBFOM). CalTrans selected the DBFOM model. Under this arrangement, the private partner (referred to as the “concessionaire”) would pay for and build the Parkway and related improvements, then operate and maintain it for 30 years. The public partner agreed to make a payment to the private partner after construction and thereafter make 28 annual payments (referred to as “availability payments”). Although in some DBFOM P3s, the private partner is repaid for its endeavors from sales, charges, or tolls related to the “concession,” in the Presidio Parkway and other P3s, the private partner’s repayment or profit comes from “availability payments,” derived from public funds such as tax revenue.
The Presidio Parkway P3 remains controversial, with debate over whether the public sector ends up paying too much over the long run, or whether the P3’s deferred payment and reduced risk justify the arrangement.
Given the limitations on direct private development in freeway ROWs, for the time being, P3s will be limited to complex transactions that facilitate building with deferred payment, or in integrated cap developments that incorporate land outside of the ROW.
Project Labor Agreement
A freeway cap project will be a unique and high-profile project. It will also involve public funding or public resources, at least in part. Such projects are uniquely suited for project labor agreements (PLA). A PLA is a collective bargaining agreement in which the developer agrees to use unionized contractors, and which sets forth the terms for such use. PLAs (aka Community Workforce Agreements) are most often used when the project uses public funding. PLAs are recognized by federal statute, which exempts them from certain NLRA requirements in order to facilitate their use. However, federal policies and presidential executive orders have see-sawed between encouraging and discouraging their use, depending on whether the administration is pro-labor or pro-free market. Additionally, state and local policies may differ between themselves and with the federal policies in force at the time. Also, local non-unionized contractors may be active and organized in opposing PLAs. Whether to enter a PLA depends on the political landscape and contractor resources at hand. PLA’s can help gain labor allies for a project, but may add expense.
 These can also be referred to as “baseline assumptions” – Roesling Nakamura Terada Architects, Inc., Kimley Horn and Associates, Inc., Economic Planning Systems, Inc., and Van Atta Associates (September 06, 2012), Ventura Beach + Town Project White Paper, City of Ventura, p.4
 Ventura Beach + Town Project White Paper, 12
 City of San Diego (2016), Downtown Community Plan, p. 5-24
 San Diego’s Capital Improvements Program Review and Advisory Committee (CIPRAC) is an example. At the time of this writing, it can be found at: https://www.sandiego.gov/cip/about/ciprac
 Ventura Beach + Town Project White Paper, 19-20
 Lau, C., AICP (2012), Urban Freeway Cap Parks Policy Briefing Paper, Los Angeles Sustainability Collaborative, pp. 16-17, Retrieved on April 25, 2018 from http://lasustainability.org/wp-content/uploads/2012/07/LASC-ClementLau-CapParksPolicyBriefing.pdf
 Ibid., 7
 Ibid., 8
 Definition of “Lead Agency” from California Natural Resources Agency website, Retrieved on Jan. 16, 2018 from http://resources.ca.gov/ceqa/flowchart/lead_agency.html
 Ibid., 22
 Joint Powers Authority. (n.d.). In Wikipedia. Retrieved September 18, 2017 from https://en.wikipedia.org/wiki/Joint_powers_authority
 California Government Code § 6500, et seq.
 de Sousa Mills, Paula C.P. (Jan. 14, 2016). The Ins and Outs of Joint Powers Authorities in California, BB&Knowledge. Retrieved on Sept. 18, 2017 from https://www.bbknowledge.com/author/paula-c-p-de-sousa-mills/
 23 CFR sec. 710.405(b)(4)
 U.S.D.O.T. Build America Bureau. Retrieved on Sept. 21, 2017 from https://www.transportation.gov/buildamerica
 Wikibooks contributors, “Public-Private Partnership Policy Casebook/Presidio,” Wikibooks, The Free Textbook Project, https://en.wikibooks.org/w/index.php?title=Public-Private_Partnership_Policy_Casebook/Presidio&oldid=2721801 (accessed September 21, 2017).
 The terms “concession” and “concessionaire” are used in the P3 Agreement for Presidio Parkway to identify the transaction and the private partner, respectively. These terms are somewhat misleading to the extent that these terms imply the type of concession arrangement in a National Park, in which the concessionaire receives it’s compensation through charges to the public for goods and services. In the Presidio Parkway, the “concessionaire” was paid directly by the public agency. Thus, the private partner, i.e., concessionaire was really just designing, building, and maintaining the project in exchange for an installment payment plan.
 Bialick, A. (Sept. 11, 2014). “Not a Freeway” — Re-Branding the Excesses of the $1.4B Presidio Parkway. Streetsblog SF. Retrieved from http://sf.streetsblog.org/2014/09/11/not-a-freeway-re-branding-the-excesses-of-the-presidio-parkway/ on Sept. 21, 2017.
 Wikibooks contributors, “Public-Private Partnership Policy Casebook/Presidio,” supra at “Solicitation Process.”
 National Labor Relations Act (NLRA), 29 U.S.C. §§ 151-169
 Project Labor Agreement. (n.d.). In Wikipedia. Retrieved September 19, 2017 from https://en.wikipedia.org/wiki/Project_Labor_Agreement
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4. Costs for a Freeway Cap:
Conceptually, it doesn’t seem like a freeway deck should cost much more than a bridge or the substructure for most high rise construction. However, cap projects tend to involve significantly more soft costs, especially regulatory costs, than traditional development projects. Perhaps these costs will come down in the future as cap structures become more common and municipal agencies and DOTs plan for them. Additionally, building in an active right of way (ROW) involves costs not encountered in land-based development. On the other hand, airspace ROWs are unlikely to involve significant site contamination clean-up. However, private development will likely involve collection and filtration of auto-emissions.
In the future, there seems to be significant potential for cost reductions in highway cap construction. As the number of projects increase, so will design breakthroughs and construction experience. In particular, highway cap projects supporting intensive commercial or residential development present intriguing possibilities. Buildings will not simply be constructed on top of platforms. Rather, building frames will be integrated with – and be essentially one with – the cap platform. Thus, rather than viewing such developments as building the land (i.e., the platform) in the highway airspace upon which buildings may be constructed, the project may be viewed as constructing buildings without the need for acquiring and preparing raw land. The buildings frames will be the “land.” At least theoretically, this presents a tremendous opportunity for savings, or at least an offset of some of the additional costs of building in freeway airspace.
Types of Costs:
Costs can be broken into three broad categories: soft, hard, and downstream. Cost categories can include the following:
|Soft Costs||Hard Costs||Downstream Costs|
|Environmental review||Acquisition / assembly of adjacent land||Maintenance of cap common areas and open space|
|Design||Cap structure construction||Programming|
|Fundraising||Improvements on cap (park, fixtures, buildings)||Energy (e.g., lighting, filtration equipment)|
|Legal||Traffic ramp improvements and realignments||Maintenance and repair of equipment (e.g., filtration)|
|Regulatory compliance||Utilities||Maintenance and repair of cap structural components.|
The costs leading up to construction will have the most variability of all the costs. However, of these costs, the architectural design and the engineering will be the most traditional and predictable of the soft costs. The Hollywood Central Park cap, a planned retrofit cap (i.e., not part of a larger freeway project) park project in Los Angeles is estimating their environmental review at between $1 million and $2 million.
Detailed data on highway decking projects is hard to come by. For example, the Park 101 District Freeway Cap Feasibility Study (August 2010, AECOM) notes “Many of the original and/or detailed cost documents associated with cap and park development were not available from the agencies charged with park construction and operation, nor from secondary sources.”
Given the similarity to bridge construction, at least regarding the load bearing structural elements, bridge construction costs give some guidance. A 2016 Arkansas guide gives a rough estimate for new bridges as $130 /s.f. but more in seismic areas. A California DOT guideline lists a range of costs for new bridges between $90 – $450 /s.f. The document identifies factors that increase or decrease the price range:
Factors for Lower end of Price Range: Short spans, low structure height, no environmental constraints, large project, no aesthetic issues, dry conditions, no bridge skew, urban location, seat abutment spread footing, no stage construction.
Factors for Higher end of Price Range: Long spans, high structure height, environmental constraints, small project, aesthetic issues, wet conditions (cofferdams required), skewed bridges, remote location, cantilever abutment, pile footing (large diameter piling), 2 stage construction.
Factors that will increase the price over the high end of the price range 25%-150%: Structures with more than 2 construction stages, unique substructure construction, [and] widenings less than 15 ft.” [capitalization modified]
– – It also notes items that are not included, such as: “. . . time related overhead, mobilization, bridge removal, approach slabs, slope paving, soundwalls, or retaining walls.”
A preliminary study in San Diego examined the cost of covering a stretch of the I-5 freeway dividing the city’s downtown from its famous Balboa Park. That section of freeway was already in a below grade trench that obviated the need for significant excavation. Additionally, there were existing bridges spanning nearly every block along that stretch. Conceptually, the study looked at decking the freeway between bridges at First Avenue through Sixth Avenue and described them as “Plazas” A –F. An additional Plaza between 7th and 8th, constituting 216,000 square feet was described as “Plaza G.” – seven plazas in total. It identified approximately 460,000 total square feet of potential deck. It included in its cost estimates: bridge construction, design engineering, construction engineering, and contingencies. It excluded: “upgrades to the existing facilities such as existing bridges, roads, or buildings.” The Plazas A through F were estimated to cost between $7.1 mil. and $12.3 mil each, and Plaza G to cost $51.6 mil, or roughly around $110 mil. total for all 7 plazas, or $240 per square feet. Costs for park development on Plazas A – F was around $1.1 mil. and $8.2 mil. for Plaza G. Building development ranged from $5.3 mil for Plaza D to $38.1 mil for Plaza G. However, a subsequent cost estimate by AECOM prepared in 2010 (Feb. 11, 2010) gives a cost estimate of $765 per square foot. or $518 mil. total. The AECOM estimate explained the substantial difference between it and the previous (Simon Wong) report, at least in part, as follows:
. . . freeway lid parks planned for Downtown San Diego are also likely to require freeway improvements when the lids are constructed. Caltrans estimates the approximate 2009 cost of these improvements to be $48,000,000 to $53,000,000 or $727 to $803 per square foot. For our preliminary cost estimate for your planning and discussion purposes, AECOM has used the mid-point within the per square foot range of cost identified in the Caltrans Supplemental PSR or $765 per square foot. Assuming the approximate combined area of 677,500 square feet for the eight lid parks in San Diego, we estimate their total cost to be approximately $518 million.
A recent study on a deck park for I-94 in San Diego puts a cost range on the unadorned deck structure at between $400 – 750 per square foot.
A 2013 presentation prepared for the City of Glendale regarding its Space 134 freeway cap concept gave cost estimates for other contemplated but unbuilt cap projects on the west coast ranging from $218 to $551 per square foot. It is presumed that since the cost estimates were listed without limitation to a particular phase or aspect, the estimates include all capital costs but not downstream costs. The project costs were as follows:
- Park 101: $551 per square foot for a 34 acre project or $413 per square foot for a 22 acre project (no explanation was given for the reverse economy of scale but likely the smaller project excluded construction of the most difficult and expensive section).
- Hollywood Central Park: $505 per square foot for a 44 acre cap (now reduced to 38 acres).
- Santa Monica Cap: $399 per square foot for a 5 acre cap.
- Olympic Sculpture Park, Seattle: $218 per square foot for a 9 acre cap.
One strategy for reducing costs is to avoid or defer the deck construction that require modifications to existing on or off ramps. On the other hand, the Park 101 Feasibility Study noted the need to:
“accommodate future widening of the freeway should Caltrans or another transportation agency deem it necessary. This is accomplished by a support system placed at a distance far enough apart to allow lane expansions without impacting the pylons supporting the cap structure itself.” (Ibid. at 4-3)
Where deck-top structures are contemplated, some cost synergy may arise from integrated construction opportunities, particularly in the shared material and coordinated construction of the bridge structure and the foundations of the buildings.
Thus, cost estimates are widely disparate, with estimates ranging from $200 per square foot to $750 per square foot. Costs are highly dependent on regional and project variables.
 See e.g., City of Glendale, Space 134 presentation, (2013) – modified from original.
 Arkansas Department of Transportation, Estimated Costs per Mile, 2016, Retrieved from https://www.arkansashighways.com/roadway_design_division/Cost%20per%20Mile%20(JULY%202016).pdf (accessed Sept. 29, 2017)
 California Dept. of Transportation, Div. of Engineering, Comparative Bridge Costs (January 2015), retrieved from http://www.dot.ca.gov/hq/esc/estimates/COMP_BR_COSTS_2014-eng.pdf (Sept. 29, 2017)
 The I-5 Downtown Deck Study Preliminary Study Report (August 26, 2003 by Simon Wong Engineering for Centre City Development Corporation – the city’s redevelopment agency aka CCDC).
 AECOM cost estimate prepared for CCDC in 2010 (Feb. 11, 2010).
 CalTrans, Freeway Cap Best Practices & SR 94 Cap Park Study (November 2016), SR 94 Freeway Cap Park Feasibility – Planning-Level Capital Cost Estimates and Planning-Level Operations & Maintenance Cost Estimate, pp.48-54, Retrieved on Oct. 16, 2017 from http://www.dot.ca.gov/dist11/departments/planning/planningpages/capstudy.htm
 City of Glendale, Space 134 presentation, (2013) – acre cost estimates converted to square feet estimates by author. All costs estimates were for projects still in planning stages.
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5. Paying for a Freeway Cap
Broadly speaking, caps can be divided into several categories for funding purposes. First, there are retrofit caps and there are caps connected with new freeway construction. Additionally, there are caps dedicated principally to public space and facilities (Klyde-Warren in Dallas, Freeway Park in Seattle) and there are private development caps (Capitol Crossing). The most “common” cap projects (if a cap project can ever be called “common”) at this time (at least until regulations change regarding private caps) are retrofit caps dedicated to public space and facilities. They are also the most difficult to fund. In contrast, new or expansion freeway projects are better able to obtain highway related funding as part of the overall highway project. Caps can be incorporated into the budget of new freeway construction, within limits, as a mitigation measure. However, park retrofit cap funding is more difficult since there is no existing source of funding to which to attach. The public tends to view them as expensive public parks. The benefits – beyond simply being a park – are yet to be widely recognized or they are viewed as not having any urgency or priority of need.
Funding a freeway cap or other freeway right of way project typically involves a patchwork quilt of funding sources. These can be categorized as government program funding sources, project based funding sources, and private capital. Additionally, the first category can be further broken down into federal, state, and local – each involving particular agencies and programs. This chapter provides an overview of various potential sources, with more detailed descriptions of various funding sources in Appendix A.
Governmental funding sources can come in the form of grants subject to an application process or in the form of legislative acts by a governing body. Grants are more typical for federal and state sources, whereas funding by legislative act is more common from local governing bodies. Additionally, Federal funding programs can be in the form of tax credits or cash funding, depending on the program. The sources of funding by local governing bodies can come from such varied sources as tax increment financing (TIF), sales tax, property tax, transient occupancy tax (TOT aka hotel taxes), development impact fees (DIF), developer contributions, and a host of other potential sources.
Grants can be particularly helpful in the early going of a freeway cap project. This is especially true for a retrofit cap. Unlike a new freeway construction cap, retrofit caps typically have little or no seed money or specialized staff for the early planning stages. There are state and federal grants that can help in generating critical analyses and documents important to the early stages of planning a freeway cap project. For example, the City of Ventura California utilized a Southern California Association of Governments Compass Blueprint grant (renamed “Sustainability Planning Grant”) early in the process for their Towne + Beach project “to examine the feasibility of creating a transit-oriented, mixed-use, waterfront downtown by capping a portion of Hwy 101.” Hollywood Central Park got started with a mixture of help from SCAG, LA’s redevelopment agency, neighborhood councils, and corporate donors.
For construction, grants will play a more limited role, and cannot be relied on for the lion’s share of construction costs, which must come from some form of project-based, state, or local funding. Nevertheless, the following federal grants, as well as applicable state grants, can comprise important components of gap construction funding:
- The Safe, Accountable, Flexible, and Effective Transportation Equity Act: A Legacy for Users (SAFETEA-LU)
- Surface Transportation Program (STP);
- Transportation Enhancement (TE);
- Congestion Mitigation Air Quality Improvement Program (CMAQ);
- Community Development Block Grants (CDBG); and
- Transportation Investment Generating Economic Recovery (TIGER);
Most of the above referenced grants require some level of local matching. There are other federal funding sources. For more specific information about these and other programs, please see Appendix A.
Tax Increment Financing
Tax increment financing is a “value capture strategy” whereby property tax revenue attributable to increases in appraised property values during a defined time period and within a defined geographical area is earmarked for infrastructure, public projects, or redevelopment within that geographical area. Because such an allocation may deplete property tax revenues going to other recipients, TIF is generally justified on the basis that, over time, it will increase property values in the designated area, thus in turn, increasing overall property tax revenue. Typically, TIF is associated with redevelopment and elimination of blight. The best known type of TIF is an urban redevelopment project. Most states have some type of tax increment financing program.
Laws regarding TIF vary by state and can be volatile. For example, in 2012, California repealed its primary TIF mechanism, the California Community Redevelopment Act. To fill part of the gap left by the redevelopment law, California enacted far more narrowly scoped TIF laws, such as the Enhanced Infrastructure Financing Districts law.  More recently, California has started to bring redevelopment TIF back via “Community Revitalization and Investment Authorities.”
Freeway lid projects are well suited for TIF. Properties near freeways, due to noise, pollution, and unsightliness, often have depressed values. Mitigating the existence of the freeway, and replacing it with a park or private development, has proven to increase the value of adjacent properties. Moreover, the building of a freeway deck in the airspace over a freeway actually creates “new land” upon which to build taxable improvements (however, private development in freeway airspace is currently limited. See Chapter 6).
Typically, there is a lengthy and complicated process for defining a TIF district. Depending on the state, that process can involve environmental review. Once a TIF district is established, it creates an identifiable revenue stream which can be used for bond financing.
Assessment or Fee Districts
Some states provide for assessment or fee districts. In certain instances, an assessment or fee district maybe a useful component in funding a freeway cap. The difference between assessments and fees is typically based on ownership or use, respectively. Such districts are a creature of state law and thus vary, if they exist at all, by state. Assessment and fee districts, to the extent revenues may be applied to capital improvements, may facilitate bond funding of projects within the district. Common types districts include the following:
In these districts, assessments apply to property ownership and typically attach to the property tax bill. The assessment revenue can be used for both capital improvements and for maintenance within the district. If created specifically for funding a freeway cap, such a district would likely include both the new land on top of the cap and adjacent properties. The inclusion of the adjacent properties would be justified under the theory that those properties benefit from the project. The new land on top of the cap, to the extent it is public space, would not generate assessments but could generate fees, such as for parking. However, private development could be subject to assessments. Assessment districts are particularly useful for creating a sustainable maintenance plan. A sustainable maintenance plan, independent of state DOT funds is typically a point of emphasis for state DOTs to approve a cap project.
Parking fee districts
This approach uses special districts and allocates funds from parking fees toward specific infrastructure projects within the district. By introducing or increasing parking fees, local governments can raise funds for a litany of infrastructural improvements and developments. Proceeds are available for both capital expenditures or operating & maintenance expenses. However, parking fee expenditures are typically determined by businesses within the district and usually are directed toward creating or maintaining parking for business customers. Nevertheless, if the proposed freeway cap will significantly add to the parking resources in the district, it may be a viable source of construction funding.
Business Improvement Districts
Business improvement districts (BID) are typically created to promote and serve businesses within the district. BID fees are usually added to the business license fee. Common uses of BID fees are marketing initiatives promoting the district to potential consumers of the goods or services of the businesses within the district. Applicable state law may even prohibit use of BID fees for capital improvements. Thus, BIDs are generally not good candidates for freeway cap funding.
Tax Increment Financing Districts
These districts are discussed separately under Tax Increment Financing.
General Obligation Bonds (GO Bonds)
A GO Bond is a bond which is secured by state or local government resources to repay the bond holders. GO Bonds rely on the city or state’s ability to repay the bonds through taxes rather than future revenue from the project. They may either be limited-tax or unlimited-tax GO Bonds. Limited-tax means the government is expected to raise property taxes as needed to pay the debt, but within statutory limits. Unlimited-tax refers to GO Bonds without such statutory limits, so that property tax may be raised up to 100% to fulfill the obligations. Bond funding is normally limited to capital expenditures.
Regional special taxes, such as local sales taxes, are sometimes a contributor to freeway cap projects. However, it is unlikely that taxes earmarked solely for freeway cap parks will pass in most jurisdictions, particularly in California which generally requires a ⅔ vote by the electorate for such taxes. If the tax is part of a larger tax package, such as a measure for parks or transportation funding, then it may be possible – although in California, such a measure would still require 2/3 voter approval.
Cities can implement taxing districts, which allow certain districts to increase sales tax rates to either pay for capital facilities or ongoing operations and maintenance. (In California, an increase is limited to a maximum of 2% and subject 2/3 voter approval.)
Transient Occupancy Tax (TOT)
Also known as a hotel tax, many cities have TOTs, which apply to visitor accommodations. They are usually levied on the gross receipts of lodging fees. TOTs can be city-wide or by district. Proceeds are available for both capital expenditures or operation and maintenance expenses.
Parcel taxes are similar to property taxes, except that a parcel tax is based upon the characteristics of a property rather than the value of the property. Common examples of parcel tax characteristics include square footage, acreage, apartment units, or status as a single-family home. As with any tax, an increase or implementation often requires approval by vote of the persons who would pay the additional tax. Proceeds are available for both capital expenditures or operations and maintenance expenses. A parcel tax is essentially indistinguishable from a property assessment.
Property tax is an ad valorem tax (proportional to value) on the value of a real property and/or improvements on real property. While there is nothing in the definition of a property tax that prevents its use to fund a freeway cap, typically most funds from a property tax are already committed, thus necessitating a property tax increase to fund a freeway cap. The process for approving a property tax increase, and for what purpose, will vary greatly from state to state. Some states, e.g., California and Washington, impose a cap on the property tax rate, limiting the power of states, counties, or cities to raise property taxes.
Tax credits typically relate to federal taxation. Rather than direct funding, tax credits provide private investors with a dollar for dollar credit towards income tax. Tax credits can make an otherwise unprofitable or economically unfeasible project into an economically feasible project. Perhaps the most applicable would be the Federal New Markets Tax Credit (NMTC), which encourages private investment in census tracts that meet certain eligibility criteria. The criteria are for the purpose of establishing that the census tract is economically disadvantaged. At first glance tax credit programs would appear ill-suited for public infrastructure, such as most freeway cap projects. However, private investment can be structured under the NMTC to help finance many types of public infrastructure. The NMTC is discussed in more detail in Appendix A.
City General Fund
City general funds are cities’ primary funding source, and they are dedicated to providing a number of fundamental city services. Access to city general funds to finance freeway caps is highly dependent upon the local government, policies, and procedures. City general funds are more likely to come into play as secondary collateral for a general obligation bond, where a primary source (such as revenue from a hotel tax increase) has been identified. It is hard to imagine a city that would fund a freeway cap project, in whole or in part, directly from its general fund.
Development Levies, Incentives, and Agreements
Requests for Proposals (RFP) and Development Agreements (DA)
RFPs and DAs apply where the city has ownership or control of the land to be developed. For example, this circumstance can include development on a planned freeway cap structure. In such a case, the City initiates the contact with developers by issuing an RFP. The City can condition approval upon the developer’s agreement to conditions. Due to the contractual nature of DAs, their parameters are largely open to the specific needs of the project.
Development Contribution or Fee
Sometimes known as development impact fees (DIF), some cities charge these fees on new development. This fee is usually a fixed percentage or unit charge contribution, based upon square footage or the number of residential units, which the developer pays to local agencies in exchange for project entitlements. Typically, DIF goes to designated projects. Therefore, it is important to have highway cap projects approved as eligible for DIF funding. For example, in San Diego “Freeway Lids” are a specific line item in its “Downtown Community Public Facilities Financing Plan and Development Impact Fee Fiscal Year 2015.” Items are prioritized as DIF 1 and DIF 2 items and given appropriation years.
Transfer of Development Rights (TDR)
TDR is defined as follows:
Transfer of Development Rights (TDR) is a voluntary, incentive based program that allows landowners to sell development rights from their land to a developer or other interested party who then can use these rights to increase the density of development at another designated location. TDR availability depends on the local jurisdiction.
Even where TDR programs are in place, highway caps aren’t traditional land to which the TDR may apply. At the least, some regulatory and planning adjustments will likely be necessary to make a TDR applicable to a highway cap. Additionally, it may prove controversial to allow developers the right to deviate from or exceed development restrictions in a neighborhood by helping to fund cap construction or construction on top of the cap. Accordingly, TDR is not likely to be a strong candidate for funding cap development, particularly as it applies to “backbone” infrastructure, i.e., the public facilities related to the cap, including the cap structure itself.
Airspace over freeways may be leased for periods up to ninety-nine years, which is a lengthy enough lease to raise private capital to fund practically all private development. In many cities, the cost of constructing a platform for buildings in highway airspace is comparable to or less than purchasing land. This is particularly true in the downtowns of thriving cities. Once the basic structural deck over a freeway is erected, private development costs are similar to building on terra firma. There may even be savings that can be achieved in the overlap between designing and constructing the building and the bridge structure and a reduction in demolition and excavation costs. However, FHWA and state regulations currently obstruct private development in freeway airspace, except in very limited circumstances (See discussion in Chapter Six).
Several of the retrofit cap projects that have been built or are in an advanced planning stage relied on private donations, particularly in the early stages. Such donations may be tax deductible, depending on the circumstances.
Public/Private Partnership (PPP or P3)
P3s allow private and public entities to work collaboratively to plan, finance, and build development projects next to or adjoined to public transportation facilities. Theoretically, P3’s can allow governmental and private entities to spread the risks of new projects, as well as pooling resources to successfully complete the project. They can be used for both for capital improvements and operation and maintenance.
The Presidio Parkway project, which included two caps over Highway 101 in San Francisco, utilized a P3. The Presidio Parkway project used the Design-Bid-Build-Finance-Operate-Maintain model (DBFOM) model. Under this arrangement, the private partner (Golden Link) paid for the Parkway and related improvements. Golden Link will operate and maintain the improvements for 30 years. The public partner (Caltrans and the San Francisco County Transportation Authority (SFCTA) agreed to make a payment to the private partner after construction and thereafter make 28 annual payments. This P3 and P3s generally were discussed more fully in Chapter 3.
Build America Transportation Investment Center (BATIC)
A resource for information on funding an infrastructure project is the Build America Transportation Investment Center (BATIC). It was established to help projects across the country learn from others’ experiences. In particular, BATIC was established to foster P3s. The BATIC is intended “to serve as a one-stop shop for cities and states seeking to use innovative financing and partnerships with the private sector to support transportation infrastructure.”
Additionally, the USDOT established the Build America Bureau to build
. . . upon the foundation established by the Build America Transportation Investment Center (“BATIC”). The Bureau serves as the single point of contact and coordination for states, municipalities, and project sponsors looking to utilize federal transportation expertise; apply for federal transportation credit programs; and explore ways to access private capital in public private partnerships.
The Bureau combines the Bureau, TIFIA and RRIF loan programs, Private Activity Bonds (PABs), and the INFRA grant program all under one roof within the Office of the Undersecretary for Transportation for Policy.
Funding possibilities for highway cap development can come from many sources: public or private; federal, state, or municipal. Therefore, diligent research is invaluable. Appendices A and, for California, B, provide a list of government funding programs. Experience helps too. Thus, having board or committee members who have extensive experience in local government or land use can prove invaluable. Creative out-of-the-box thinking can be another useful endeavor, and helps in the recognition of unobvious opportunities. If a highway cap can be part of the solution for another problem – even a problem that has yet to be recognized – it may access funding normally reserved for other capital expenditures. For example, in my city San Diego, we finally built a new public library that was worthy of a major city. The city did it with significant funding from the school district. Two stories of the library were built for a new urban high school. The inclusion of the school provided the gap funding needed to complete the library. Another school in downtown sits on leased park land adjacent to the freeway and across from Balboa Park. The lease was expiring. The school paid virtually nothing for the lease. At the time the school district wanted to extend the lease, there may have been an opportunity to have the school district help fund a freeway cap to extend the park and mitigate the unhealthy air at the school. In essence, the funding would have created land to offset the park land lost to the school by extending the lease. (Unfortunately, this scenario did not transpire) Transportation projects, convention centers, and the like can create public funding opportunities. With sufficient air quality remediation, even housing can be located on or adjacent to cap structures.
 Southern California Association of Governments (SCAG), Sustainability Planning Grants, Retrieved on Jan. 18, 2018 from http://sustain.scag.ca.gov/Pages/Grants%20and%20Local%20Assistance/GrantsLocalAssistance.aspx
 Roesling Nakamura Terada Architects, Inc., Kimley Horn and Associates, Inc., Economic Planning Systems, Inc., and Van Atta Associates (September 06, 2012), Ventura Beach + Town Project White Paper, for City of Ventura, page 1.
 Federal Highway Administration, Office of Legislation and Intergovernmental Affairs, Program Analysis Team, A Summary of Highway Provisions in SAFETEA-LU (August 25, 2005), Retrieved on Nov. 27, 2017 from https://www.fhwa.dot.gov/safetealu/summary.htm
 Wikipedia, Tax increment financing, Retrieved on Nov. 22, 2017 from https://en.wikipedia.org/wiki/Tax_increment_financing
 In 2014, California enacted a law allowing Enhanced Infrastructure Financing Districts [EIFD] as a partial replacement for redevelopment TIF. An EIFD allows the adoption of an infrastructure financing plan and issuance of bonds, for which only the designated district is liable, upon approval by 55% of the voters [within the district]. An EIFD is allowed to fund public infrastructure in the district.
 Reed, Chris, New law clears way for redevelopment’s return, CalWatchDog.com (Oct. 2016), Retrieved on Nov. 22, 2017 from https://calwatchdog.com/2016/10/01/new-law-clears-way-redevelopments-return/
 Investopedia. (n.d.). General Obligation Bond- GO. Retrieved from http://www.investopedia.com/terms/g/generalobligationbond.asp
 Duran, Robert, New Markets Tax Credits – the Best Kept Secret in Financing Public Projects, (Feb. 1, 2017) BBKnowledge by Best, Best & Krieger, LLP, Retrieved on Nov. 22, 2017 from https://www.bbknowledge.com/economic-development/new-markets-tax-credits-the-best-kept-secret-in-financing-public-projects/
 City of San Diego, Downtown Community Public Facilities Financing Plan and Development Impact Fee Fiscal Year 2015, p. 7, retrieved from http://www.sandiego.gov/facilitiesfinancing/pdf/plans/downtownpffpfv.pdf
 University of Wisconsin Stevens Point, Center for Land Use Education, Planning Implementation Tools Transfer of Development Rights (TDR), retrieved from https://www.uwsp.edu/cnr-ap/clue/Documents/PlanImplementation/Transfer_of_Development_Rights.pdf
 Backbone infrastructure is described in Economic & Planning Systems, Inc., Final Draft Financing Strategy
U.S. 101 Ventura Capping Project Phase 2, (September 5, 2012), p. 11:
“The term “backbone infrastructure” is often used to describe all publicly owned facilities. This report uses the following definitions to characterize these items more precisely:
• Backbone Infrastructure. This term includes most of the essential public service-based items that are underground or on the surface. Backbone Infrastructure is sized to serve the Project and in some cases serves broader development areas. For the Project, Backbone Infrastructure includes the following items:
— Grading. — Roadways.
— Freeway/Freeway Cap.1
• Public Facilities. This group of items comprises on-site amenities to the Project (e.g., parks) or houses employees providing services to the area (e.g., police, fire). For the Project, Public Facilities includes the following item:
— Parks and plazas. — Bus Infrastructure.
— Landscaping.2 — Promenade Improvements.
— Pier extension improvements. — Trestle bridge conversion.
— Dune restoration. — Parking facilities.
This report also contains a description of potential vertical construction (e.g., structured parking, commercial) and associated costs envisioned for development on the cap. It is anticipated that a public-private partnership will be formed to develop these land uses.”
See Appendix I: Financing Strategy, in Roesling Nakamura Terada Architects, Inc., Kimley Horn and Associates, Inc., Economic Planning Systems, Inc., and Van Atta Associates (September 06, 2012), Ventura Beach + Town Project White Paper, City of Ventura.
 Wikibooks contributors, “Public-Private Partnership Policy Casebook/Presidio,” Wikibooks, The Free Textbook Project, https://en.wikibooks.org/w/index.php?title=Public-Private_Partnership_Policy_Casebook/Presidio&oldid=2721801 (accessed September 21, 2017).
 USDOT. (July 13, 2015). San Francisco’s $1.1 Billion Presidio Parkway Completed. USDOT Press Releases. FHWA 52-15. Retrieved from https://www.fhwa.dot.gov/pressroom/fhwa1552.cfm
 See Appendix B for California-specific funding sources.
© All rights reserved (2018)
6. Private Freeway Cap Development:
Use of highway airspace for private projects holds great future potential. Unfortunately, private development thus far has been prevented by FHWA regulations which deter banks and other private investors from financing private development of or on freeway decks.
Public Policy Reasons to Encourage Private Development in Freeway ROWs
While not presently possible, there are numerous reasons for private ventures to want to build in highway airspace, including:
- Space: Highway airspace can provide large and contiguous developable space in urban areas with a shortage of buildable space.
- Incentives: Exposed highways in urban surroundings are highly undesirable to adjacent uses. Eliminating the negative impact of exposed highways, and replacing it with compatible development justify incentives to development, including relief from height, mass, parking, and other design requirements.
- Revenue: Private development in airspace can create long term revenue streams for local government and state transportation agencies through “in lieu of property tax” and rent revenue streams.
- Land Assemblage. Municipalities and the state can avoid land assemblage problems and the use of eminent domain for large public projects that would otherwise be built on privately owned land.
- Health: Highway caps can mitigate the negative impact on health to nearby populations from highway air and noise pollution. Such benefits are uneven and need to be further explored. In any case, to the extent that private development increases overall covering of highways, as well as creates revenue streams, the use of such highway coverings should accelerate the ability to design coverings that will mitigate pollution.
Regulatory Obstacles to Private Development in Freeway ROWs
The Code of Federal Regulation sections governing Right of Way Use Agreements does not ban nor even discourage private development in FHWA ROWs. Rather, it contains a provision that acts as a “poison pill” to private development. The purpose of the provision is to ensure there is room for expansion, if needed, of any highway in which the FHWA has invested funds. In particular, 23 CFR § 710.405(b)(4) requires that such agreements “[e]stablish terms for revocation of the ROW use agreement and removal of improvements at no cost to the FHWA.” The Airspace Guidelines for ROW goes on to explain that each agreement should contain provisions to:
“Revoke the agreement in the event that the airspace facility ceases to be used or is abandoned, or becomes necessary for highway purposes” and
“[A]ssure full understanding that the airspace user will not qualify for relocation benefits under the Uniform Act.”
While the regulations state that “[t]he terms and conditions listed in the guidance are not mandatory requirements,” the CFR requirement for “removal of improvements at no cost to the FHWA” appears sufficiently damning on its own. Additionally, these requirements are duplicated in some state DOT regulations. California is such a state. As a result, California has no privately funded or developed freeway caps.
Banks and other investors cannot tolerate uncertainty in the form of a revocation-at-will clause – not to mention without reimbursement – regardless of how unlikely such an event may be. As a result, private development requiring major financing will be – on a practical level – limited to non-FHWA airspace, i.e. airspace of rights of way that were not acquired, in whole or in part, with FHWA funds. Private development projects built on non-FHWA ROWs include projects like Hudson Yards in Manhattan (built over an active train depot and rail yards) or Capitol Crossing in Washington D.C. (built over a section of I-395 with an easement over land owned by the City). Nevertheless, these projects demonstrate the vast potential for private coverage of freeways if this regulation were removed and private development were encouraged.
Because of the regulatory impediment to financing private development, up to this time, the overwhelming number of highway airspace projects have been public uses such as parks and convention centers. Even in a state as large, populous, and freeway dominated as California, there is no private development of or on highway deck projects.
The purpose of the regulation’s revocation provision – i.e. preserving highway ROWs where expansion maybe necessary in the future – can be attained with procedures that do not have the effect of eliminating all private ROW development. For example, many freeways will never be expanded. Some are even being considered for removal. In other instances, potential expansion can be accommodated by constructing a freeway cap project to accommodate expansion. Rather than require that ROW use agreements to contain revocation-at-will provisions, the regulations could require DOTs to ensure that either there will be no future need for expansion of the ROW or that the freeway cap project be constructed to accommodate forseeable expansion. The relevant DOTs can implement procedures to evaluate such expansion needs. To some extent, this process is already occurring. For example, California’s Freeway Best Practices Guide requires that caps be designed and constructed to accommodate future expansion.
It will likely take an act of Congress, or the Executive Branch, to modify the regulations and facilitate private development of highway cap structures. On the other hand, perhaps some creative financial or legal minds will develop a work-around. The likelihood of the FHWA or state DOT revoking a ROW use agreement for a substantial cap project seems remote – but is real enough to prevent private financing. Perhaps the remoteness of the possibility, and offsetting revenues to a city, make it feasible for a city to assume the risk of revocation via insuring or guaranteeing reimbursement of private financiers. In turn, perhaps a city’s assumption of risk would make private financing and private cap development viable. The author is not aware of any project in which this arrangement has been tried.
Other regulations that deter private development include the following:
- The state transportation agency must determine and receive the fair market value of the airspace at issue, particularly if Federal funds were used to acquire the highway right of way. The state lease revenue must be applied to Federal Title 23 transportation uses, although such application does result in an offsetting credit against the state’s future receipt of such funds. These requirements in their application can be a conflict point. Given that the airspace would unlikely have any other productive use and given that private development will generate possessory / in-lieu, sales, and other tax revenue, there seems to be no justification for SDOT’s to recover more than they spend on cap development.
- Advertising signage is limited to identifying ownership and activity.
Even with the regulations, it’s possible to build and lease space to private entities in or on public caps, but these will likely be limited to small retail or non-profit facilities. As long as highway airspace decks are limited to public uses or small private uses, it seems likely that the pace of covering highways will remain very slow due to the funding priorities for public projects.
Financial Feasibility of Private Development in FHWA ROWs
The cost of land in Manhattan averaged $578 per square foot in 2015 and $183 per square foot in Brooklyn. However, Manhattan land prices have been as high as $1,375 per buildable square foot. Id. The most expensive land purchases in downtown San Diego – allowing high density development – San Diego have ranged from $500 – $700 per square foot. Outlier prices include $4,075 per square foot for a downtown Chicago lakeside property for high rise residential development, although the lot was valued by its prior owner at less than half that amount. Land in non- booming downtowns of major cities can range from $50 – $250 per square foot. In comparison, creating “land” in highway airspace likely costs between $300 to $750 per square foot. But some of the cap construction cost maybe offset by the elimination of the costs of demolition, grading, and foundation construction for a land development project.
Generally speaking however, freeway-airspace deck development is more expensive than land development, particularly when such development must pay for construction of the deck – all or in part. One method to offset the additional cost of deck construction is to develop an incentive program. Incentives can include such things as tax incentives, elimination of minimum parking requirements, relief from height / density restrictions, reduced permitting fees, streamlined permitting procedures, or any other of a number of incentives commonly applied to encourage development in blighted areas.
 US DOT – FHWA, Airspace Guidelines to 23 CFR 710.405 – 710.407 (revised August 10, 2010), retrieved from http://www.fhwa.dot.gov/real_estate/right-of-way/corridor_management/airspace_guidelines.cfm
 In California, “airspace lease agreements on Caltrans right-of-way include provisions governing lease revocation [under which] . . . Caltrans may terminate airspace leases at any time for purposes related to [state highway system] operations and maintenance, generally at no cost to Caltrans. Typical airspace lease agreements allow for the development of caps, but lack the certainty needed by investors to justify costs.” CalTrans (2017), Freeway Best Practices Guide, Final Draft, p. 5-3; Retrieved on April 4, 2018 from http://www.dot.ca.gov/hq/tpp/grant_files/final-products/11_FwyCapBestPracticesGuideFinalDraft_03122017_Watermark.pdf
 Roesling Nakamura Terada Architects, Inc., Kimley Horn and Associates, Inc., Economic Planning Systems, Inc., and Van Atta Associates (September 06, 2012), Ventura Beach + Town Project White Paper, City of Ventura, p.18
 CalTrans (2017), Freeway Best Practices Guide, Final Draft, supra, p. 5-3
 Freeway Best Practices Guide, Final Draft, supra, p. 5-1
 Title 23 CFR § 710.403(d)
 Hughes, C.J., The dirt on NYC’s soaring land values, The Real Deal – New York Real Estate News (April 2015), Retrieved from https://therealdeal.com/issues_articles/486631/
 Gallun, Alby, Most precious thing in downtown Chicago? Dirt, Crain’s Chicago Business (Oct. 2014) Retrieved from http://www.chicagobusiness.com
© All rights reserved (2018)
7. Environmental Justice and Filtration Technology in Covering Highways
Health Impacts of Auto Emissions Near Highways:
The ultra-fine particulates and chemicals injected into the air from busy highways inflict premature deaths, chronic illnesses, birth defects, and other impacts on nearby residents and employees. 53,000 U.S. deaths annually are attributable to automobile emission air pollution. Many more people become chronically ill or incapacitated as a result of auto emission exposure and related illnesses. Ninety percent of the cancer risk from air pollution in Southern California is attributable to auto emissions.
Moreover, these health impacts are among the most unfair of preventable hazards to human health. The impacts are largely imposed on populations without their consent or knowledge. Children are disproportionately impacted. Biologically, children are more sensitive to pollutants and they present a longer life span for the health impacts to manifest. The Environmental Protection Agency (EPA) has recognized the need to site schools away from high emission roadways and install filtration in schools already located near such roads. The continued construction of multi-unit residential buildings in Los Angeles has been controversial. Of course, high emission urban roadways are lined with residences, businesses, and schools on a massive scale.
The health hazards of spending significant time near or in highway traffic are still not well understood by the public. If theses health hazards received attention proportional to other health hazards, it likely would lead to significant economic and social disruption. The habitability and value of homes and businesses within 1,000 to 2,500 feet of either side of highways would come under scrutiny. Near-highway zones could carry health warning signs, sales could require disclosures, and uses involving children could be banned or condemned. Instead, homes, businesses, and schools continue to be built near busy highways. Moreover, under the banner of transit oriented development (TOD) and city density goals, the residential developments near highways tend to be taller and denser than residences further away. Additionally, busy highways have historically been built in less economically influential neighborhoods and affordable housing tends to be built closer to the highways – resulting in an obvious health and safety bias against economically disadvantaged communities.
Ironically, most regulatory emphasis to date on filtration of cap and tunnel structures has been for the benefit of the automobile occupants under the cap or in the tunnel rather than for the benefit of the adjacent residents, school children, and employees. This seems unfair given that the adjacent residents, children, and employees have longer and more permanent exposure to the emissions, and perhaps less choice in the exposure.
Hopefully, the transition to electric vehicles and emission reduction requirements will significantly lessen this hazard by the time new highway airspace decks are completed. Nevertheless, air quality issues will persist. Legacy vehicles will continue to emit toxic particles and gasses for some time into the future. Additionally, the health impact of particulates from brakes and tires have not been fully studied.
Highway airspace deck structures, by virtue of their proximity to traffic, naturally raise issues concerning air quality. They also present opportunities to mitigate highway air pollution. Highway caps structures tend to reduce pollution adjacent to their midsections. This circumstance is accomplished by essentially trapping or redirecting the escape of particulates and gasses. Without more, this does not eliminate the pollutants, which may be concentrated in the below-deck tunnel and at the ends thereof. Decks also present opportunities to vent and filter pollution. European countries and Japan, with their greater number of longer tunnels, are leading the way in the research and development of effective treatment equipment.
Types of Filtration:
There are several types of filtration systems, some with different objectives. Most broadly speaking, there are systems designed primarily to remove particulates and there are systems designed to remove gases. Particulates have the greatest documented health impacts, and thus have been the focus of most filtration systems. These types of filtration systems can be further divided into two main types:
- Extraction systems that remove air from the tunnel or underpass, filtering particulates or gases on the way out. This type of system can utilize different types of filtration technology, including electrostatic filtration as well as biofiltration or bag filters. However, extraction systems may create an issue as to where the air is exhausted. Nevertheless, these systems tend to be used more often when the primary concern is pollution impact on the nearby community.
- Bypass systems that recirculate polluted air, after filtration, back into the tunnel. Most of the longest tunnels contain this type of system. It requires lengthy venting, either to the side of the roadway or above the road / under the deck. These systems tend to be used more often used when visibility and air quality within the tunnel are the primary concerns.
Both of these systems have been primarily designed for subterranean tunnels rather than tunnels resulting from man-made caps. However, the technology and impacts would seem to apply equally to highway caps.
Costs of Filtration Systems:
Cost data is uncertain and limited due to the relatively small number of existing filtration systems, their different technologies, different physical settings, different international locations, and different operating cycles. Operating costs tend to be high relative to installation cost. Energy consumption is generally the most expensive cost.
Capital costs in the period between 2000 and 2010 were in the range of $2 mil. to $5 mil. Annual operating costs for 24 hour operation, including energy consumption, were in the $500,000 range. However, most filtration systems were in operation far less than 24 hours per day – perhaps in large part due to the cost – but certainly filtration need changes with traffic volume, which changes throughout the 24 hour cycle. Cost may be significantly lower when installation of a filtration system is in the original design for cap or tunnel, rather than by retrofit at a later date.
Survey of Filtration Technology:
- Electrostatic Filtration: By far, this type of filtration is the most common in large tunnel applications. It uses electricity to charge (ionize) particles, which are then collected by electrodes – usually electrified plates – with an opposite charge.
- Bag Filters: Commonly used in industrial settings, bag filtration has a proven track record in those settings. However, they have proven less effective than electrostatic filtration in tunnel settings.
- Biofiltration: (see illustration below) In its infancy, current implementation is primarily to deodorize air in wastewater treatment. Researchers are investigating its application to emission pollutants – both particulate and gaseous. Such filtration involves a substrate including, e.g., sand or peat, select plants, and a “vegetated filter” and collection system. The benefits of such a system include low environmental profile – passive and renewable. Several French agencies carried out an experiment using biofiltration in a tunnel in France between 2012 and 2014. As stated in the CETU paper:
The biofilter was installed in the Guy Môquet tunnel, on the A86 motorway in Thiais (Val-de-Marne) – a 650-metre-long, bi-tube “cut and cover” tunnel with three traffic lanes in each direction, carrying 134,000 vehicles per day.
The experiment produced particulate filtration rates of between 30% and 90%, depending on particulate size, and 58% for NO2, with no loss of efficacy after 18 months. Biofiltration holds promise both as the sole filtration method or in combination with electrostatic filtration.
The Capitol Crossing highway cap project in the nation’s capitol, currently under construction, will feature “eco-chimneys that employ biofilters to clean exhaust and other toxins from the highway and integrated parking structure, returning clean air to the environment,” claims the architectural literature.
- Cold Plasma (in research and development, no current tunnel application) – This filtration technology involves using ionized gas to filter contaminated air. It holds promise for cost effectively filtering both particles and gases. It is likely to be some time yet before this technology is ready for tunnel applications.
Capitol Crossing “Eco-Chimneys.” Image courtesy of Property Group Partners.
Gas filtration systems are in much more limited use currently than particulate filtration systems. There are only four tunnels worldwide as of 2016 with gas filtration. These systems all focus on the treatment of NO2, a key ingredient in the creation of smog. In their implementation, these systems are typically integrated with a particulate filtration system – particulates necessarily being removed before gases. Because of the limited implementation of these systems in large scale tunnel applications, there is little data on effectiveness. The types of systems in use or in development include: 
- Absorption Denitrification: In this technology, treated gas undergoes a chemical reaction so that it will adhere to a solid surface. Activated carbon filtration is the most common form of this technology. In Japan, a pioneering filtration system of this type is using potassium hydroxide in the ChuoKanjo-Shinjuku tunnel near Tokyo. The system performance drops off by about 10% over 8 – 10 months but is easily regenerated.
- Adsorption Denitrification: In contrast to absorption denitrification, in adsorption denitrification (ab vs. ad) technology, gases are not altered or degraded before adhering to a solid material. Typically, this technology runs the gaseous air through containers holding pellets which “adsorb” the gases in their pores.
- Photocatalytic Denitrification: This technology uses titanium oxide (TiO2) and ultraviolet light to break down nitrogen oxides. The technology has proven fairly effective (with 15% – 30% NO2 reductions) in a tunnel in a Rome. However, there is concern about the health and environment impact of nanoparticles released in the process.
- Biofiltration of gasses is essentially the same system described earlier in this chapter for particulate biofiltration and has the same limitations.
- Cold Plasma to filter gasses (and also particulates) is promising for effectiveness, ease of implementation, and cost. However, it is still being researched. It is unlikely that this technology will be seen in a tunnel setting in the near future. In this process, an ionized gas (“plasma”) is used at ambient temperature (“cold”) to react with toxic gasses in such a way as to convert them into harmless gasses.
Maintenance, Cleaning, and Disposal:
All of these systems require periodic “regeneration” of the filter mediums. In the case of activated carbon, regeneration requires replacement after a period of 1 – 3 years. Several of the other systems are regenerated via automated cleaning processes. In these automated or ‘self-cleaning’ filtration systems, cleaning intervals generally occur every several days, with replacement required after several years. The cleansing solution is most typically water, which itself must be filtered before disposal. Where the solution is a chemical, additional measures are necessary.
As noted by the Tunnels Study Center (CETU) in France in its 2010 paper (updated 2017), The Treatment of Air in Road Tunnels – State-of-the-Art of Studies and Works:
“Before turning to systems that may effectively provide an answer to local pollution concerns, conventional ventilation techniques should still be considered by making use of the appropriate means, i.e. playing on the air flows and concentrations of the discharged vitiated air, as well as on the location and configuration of discharges and any other method likely to improve the dispersion of pollution and so protect the most at-risk areas.”
Some of the companies on the forefront of tunnel filtration are:
- Aigner (Austrian)
- Filtrontec (German)
- Panasonic (Japanese)
- CTA (Norwegian)
In conclusion, highway caps do not offer a global, or even a widespread, opportunity to mitigate highway emissions. They also are not a cost-effective method if mitigation is the only reason for building one. However, they do present an opportunity for mitigation in the limited urban locations where they are feasible. Additionally, as one of multiple reasons for building a cap, mitigation can help to justify construction of a cap. Moreover, emission mitigation impact can be valuable in gaining support for the construction of a highway cap.
Capitol Crossing sustainability features. Illustration courtesy of Property Group Partners.
 Adams, William “What is a safe distance to live or work near high auto emission roads?” UrbDeZine (2015) Retrieved from https://sandiego.urbdezine.com/2015/05/28/what-is-a-safe-distance-to-live-or-work-near-high-auto-emission-roads/
 Calazzo, F., Ashok, A., Waitz, I.A., Yim, S.H.L., Barrett, S.R.H. (2013) Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005, Laboratory for Aviation and the Environment, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, August 2013. Retrieved on Jan. 22, 2018 from http://lae.mit.edu/wordpress2/wp-content/uploads/2013/08/US-air-pollution-paper.pdf
 Hulsey, B., Hopkins, E., Olson, E., Burg, E., and Carlson, M. (2004) Highway Health Hazards: How highways and roads cause health problems in our communities—and what you can do about it, Sierra Club, 2004, 6, par. 10. Retrieved on Jan. 22, 2018 from http://vault.sierraclub.org/sprawl/report04_highwayhealth/report.pdf
 U.S. Environmental Protection Agency (Nov. 2015), Best Practices for Reducing Near-Road Pollution Exposure at Schools, Retrieved on January 22, 2018 from https://www.epa.gov/sites/production/files/2015-10/documents/ochp_2015_near_road_pollution_booklet_v16_508.pdf
 Barboza, Tony and David Zahniser, L.A. officials push for new steps to address health risks from homebuilding near freeways (March 24, 2017) Los Angeles Times, Retrieved from: http://www.latimes.com/local/lanow/la-me-ln-freeway-pollution-study-20170324-story.html
 Best Practices for Reducing Near-Road Pollution Exposure at Schools, Supra
 Lau, Clement AICP (2012), Urban Freeway Cap Parks Policy Briefing Paper, (for Los Angeles Sustainability Collaborative), p. 19, retrieved from http://lasustainability.org
 Id. at p.15.
 See id. at p.20 re M5 East tunnel near Sydney.
 CETU, supra, pp. 28 – 29.
 CETU, supra, pp. 22 – 24
 Id. at pp. 26 – 27
 Id. at p. 24
 Id. at p. 30
 Id. at p.17
- New South Wales Government (Australia) Advisory Committee on Tunnel Air Quality – Roads and Maritime Services (July 2014) TP08: Options for treating road tunnel emissions, Retrieved on Jan. 22, 2018 from http://www.chiefscientist.nsw.gov.au/__data/assets/pdf_file/0008/54791/Road-Tunnels_TP08_Options_for_treating_road_tunnel_emissions.pdf
© All rights reserved (2018)
8. Regulations, Process, and Leasing Airspace for a Freeway Cap
Highway airspace projects, such as freeway caps, are allowed under federal law and various state laws, subject to significant procedures, restrictions, and requirements. Airspace projects typically require a lease of airspace from the state transportation agency, environmental review and compliance, design review and approval, and construction oversight.
State departments of transportation (SDOTs) are largely responsible for managing highways and related airspace. However, this responsibility is subject to federal regulations if the highway is part of the Interstate Highway System or part of the National Highway System. Additionally, the Federal Highway Administration (FHWA) oversees the SDOTs in the administration of its regulations and, with respect to interstate highways, is directly involved in the approval process.
Highway cap projects for public purposes are feasible, although most project proponents who have brought a freeway cap project to fruition will attest that the state and federal involvement adds significant cost and time to the project compared to projects on privately owned or municipality owned land. As previously noted, private development in freeway airspace is currently infeasible (with a few notable exceptions) due to a regulation that makes private financing unavailable. This regulation appears to be obsolete and private development appears to hold promise for the future, should the regulatory barrier to private financing be removed.
U.S. Department of Transportation Regulations
The Federal Highway Administration (FHWA) “supports State and local governments in the design, construction, and maintenance” of the Country’s highway system. The FHWA is an agency within the U.S. Department of Transportation (USDOT). Both were created in 1966.
The FHWA has had several predecessors: The Office of Road Inquiry (1893), the Office of Public Roads (1905 – a division of the United States Department of Agriculture), the Bureau of Public Roads (1915), the Public Roads Administration (1939), the Federal Works Agency, and then reverted back to Bureau of Public Roads (1949 – under the Department of Commerce).
Many of the key regulations governing highway airspace projects are found in Title 23 of the Code of Federal Regulations (CFR) §§ 710.401 – 710.409. The regulations administered by the FHWA allow “airspace leases” over its highways, i.e., interstate highways:
(c) Other use or occupancy. Subject to 23 U.S.C. 111, the temporary or permanent occupancy or use of right-of-way, including air space, for nonhighway purposes and the reservation of subsurface mineral rights within the boundaries of the rights-of-way of Federal-aid highways, may be approved by the Administrator, if he determines that such occupancy, use or reservation is in the public interest and will not impair the highway or interfere with the free and safe flow of traffic thereon.
Final approval from the FHWA is required for any such lease. It also is a “very interested party” in airspace leases over other highways, particularly those that are part of the National Highway System (NHS).
The Interstate Highway System is formally titled The Dwight D. Eisenhower National System of Interstate and Defense Highways, which was authorized by the Federal Aid Highway Act of 1956. The Interstate Highway System is comprised of those routes typically designated with the letter “I” followed by a number. It is a subset of the NHS, which is a system of roads deemed strategic to national interests by the National Highway System Designation Act of 1995. In addition to interstate highways, the NHS includes (quoted from NHS website):
- Other Principal Arterials: These are highways in rural and urban areas which provide access between an arterial and a major port, airport, public transportation facility, or other intermodal transportation facility.
- Strategic Highway Network (STRAHNET): This is a network of highways which are important to the United States’ strategic defense policy and which provide defense access, continuity, and emergency capabilities for defense purposes.
- Major Strategic Highway Network Connectors: These are highways which provide access between major military installations and highways which are part of the Strategic Highway Network.
- Intermodal Connectors: These highways provide access between major intermodal facilities and the other four subsystems making up the National Highway System. A list of all official NHS Intermodal Connectors is available online.
What is meant by “very interested party” and what that entails for leasing and building in airspace isn’t entirely clear. However, state right of way manuals generally reveal a significant difference in procedure for projects over interstate highways compared to other NHS highways. For example, Chapter 15 of the California Right of Way Manual distinguishes final approval of interstate projects from other highways, stating:
Sites on the Interstate require FHWA approval of the final construction plans, environmental document, and, if necessary, an air quality study.
Regarding leasing, it states:
FHWA approval of airspace leases is required only when the airspace site is located on an Interstate highway. All federal requirements in 23 CFR 710.405 shall be followed.
The California manual includes a summary table of the FHWA approvals necessary for interstate highway airspace:
|FHWA APPROVAL OF AIRSPACE SITES ON THE INTERSTATE REQUIRED FOR:|
|• Conceptual use of an airspace site not in the current inventory. (Requires a narrative describing the use and a location map.)|
|• A change in use (whether new lease, assignment, amendment, etc.).|
|• Preliminary and final approval of the proposed use, including site plans, on any airspace site within the right of way (Includes telecom sites).
Note 1: Preliminary approval not required if only minor improvements (paving, striping, lighting) will be made.
|• Categorical Exemption or Environmental Impact Document of any new lease or a new lessee if the previous Categorical Exemption is over five years.|
|• Air Quality Statement.|
The FHWA contains an online list (with hyper-links) to the online locations of many states’ right of way manuals or guidelines. The applicable state manual or guidelines will be one of the most important resources for any contemplated highway airspace project. The manuals are guides to both the state and federal processes and substantive rules, necessary to gain approval for highway airspace leases and projects. Some states have additional useful materials. For example, the California DOT (Caltrans) is developing a “Freeway Cap Best Practices Guide,” which was still in draft form at the time of this writing.
Allowed Uses in Highway Airspace:
Lease of highway airspace is allowed for a broad range of public and private uses (including parking). However, the FHWA or state agency may reject airspace leases involving unsafe uses, such as the storage of flammable or explosive material, or where the airspace is needed for future operation, maintenance, or expansion of the highway.
Particularly since the Sept. 11, 2001 terrorist attacks on the World Trade Center in New York City and on the Pentagon, security is a major concern in all construction in highway airspace. Obtaining an independent safety and security analysis is advisable and may expedite approval of the project.
Fair Market Value
The state transportation agency must determine and receive the fair market value of the airspace at issue, particularly if Federal funds were used to acquire the highway right of way. The state lease revenue must be applied to Federal Title 23 transportation uses, although such application does result in an offsetting credit against the state’s future receipt of such funds.
However, there are exceptions to the requirement that the FHWA or state agency receive fair market value for the airspace. For example, the Colorado Dept. of Transportation (CDOT) Right of Way Manual interprets the federal regulatory language as follows:
CDOT clearly shows that an exception is in the public interest for:
- Social, environmental, or economic purposes;
- Non-proprietary governmental use;
- Or uses under 23 U.S.C. 142(f), Public Transportation;
- Use by public utilities as outlined in 23 CFR, Part 645;
- Railroads may be accommodated in accordance with 23 CFR, Part 646;
- Bikeways and pedestrian walkways in accordance with 23 CFR, Part 652;
- Use for transportation projects eligible for assistance under Title 23 of the United States Code 710.403(d)(5).
The CDOT manual goes on to specify:
With regard to airspace on an Interstate Right of Way, the FHWA may, upon written submission, approve an exception to the FMV requirement if the above criteria are met. The FHWA has delegated approval for less than FMV disposals on noninterstate right of way and property purchased without the use of federal funds to the Property Management Program Manager if the disposal meets with the above criteria.
The Federal Airspace Guidelines contain a number of structural guidelines, a sampling of which include:
- Structural supports must be clear of the shoulders or safety walks but, with FWHA or state agency approval, may be located in the median or “outer separation” if there is sufficient width. Structural supports must not impede visibility or traffic flow, and should allow as much space as feasible on the sides of the highway sufficient clearance to facilitate maintenance and repair work.
- Vertical clearance must be no less than 16 feet 6 inches at any point or whatever the state requirement is plus 6 inches. Where control or directional signs are installed below an overhead structure, the minimum vertical clearance between the soffit of the overhead structure and the highway grade line shall be 20 feet. Exceptions to the signage clearance requirement may be granted on an individual basis.
- Airspace projects must be no longer or wider than will allow natural ventilation. Exceptions may be made when artificial ventilation is provided.
- Design and operation should restrict access by vehicles that might be used for terrorist activities, including the carrying of explosives, e.g., by use of bollards to limit vehicular access.
- Highway alignment may not be altered, either temporarily or permanently. Exceptions may be granted if beneficial to the operation or maintenance of the highway.
Advertising signage is limited to identifying ownership and activity, and will be subject to Federal and local restrictions on signage.
Required Lease Terms
The FHWA Airspace Guidelines set forth the key required lease terms, as follows:
- Provision to prohibit the transfer, assignment, or conveyance of the airspace rights to another party without prior state department of transportation / state highway authority (SDOT/SHA) approval with FHWA concurrence on Interstates.
- Provision to revoke the agreement in the event that the airspace facility ceases to be used or is abandoned, or becomes necessary for highway purposes.
- Provision to revoke the agreement if the terms of the lease are breached and such breach is not corrected within a reasonable length of time after written notice of noncompliance has been given. In the event the agreement is revoked, the SDOT/SHA may request the removal of the facility occupying the airspace. The removal shall be accomplished by the responsible party in a manner prescribed by the SDOT/SHA at no cost to the FHWA. An exception to facility removal is permitted when the improvements revert to the State upon termination of the agreement and the SDOT/SHA chooses to accept them.
- Provision to allow SDOT/SHA and authorized FHWA representatives to enter the airspace facility for the purpose of inspection, maintenance, or reconstruction of the highway facility when necessary. The manner of when and how these inspections are to be made should be specified in the airspace agreement.
- Provision that the facility to occupy the airspace will be maintained so as to assure that the structures and the area within the highway right-of-way boundaries will protect the highway’s safety and appearance, and that such maintenance will cause no unreasonable interference with highway use.
- Provisions assuring that the airspace user will be responsible for any resulting hazardous waste contamination without liability to the SDOT/SHA and FHWA.
- Provisions to assure full understanding that the airspace user will not qualify for relocation benefits under the Uniform Act.
For examples of airspace leases see Appendix I for a copy of the airspace lease for the Kansas City Bartle Hall Convention Center, Appendix J for a California form airspace lease (probably for more mundane projects e.g., cell phone towers and under freeway storage facilities), and Appendix L for an early draft of the complex P3 Presidio Parkway project.
Approval Process / States
The approval process for a freeway cap is administered primarily by the states, i.e., SDOTs. For projects in interstate freeway airspace, the FHWA reserves direct approval authority at key junctures, including final approval.
As previously mentioned, the FHWA contains an online list (with hyper-links) to several states’ right of way manuals or guidelines. The manuals set forth state procedures for contemplated highway airspace projects.
California’s process is instructive. In that state, an airspace project is initiated by submitting a written proposal to the relevant Caltrans (the state’s DOT) district. After an initial review, the project sponsor may conduct a more detailed feasibility study in consultation with Caltrans staff. This study is called the Cap Feasibility Study (CFS), which will look at:
- Transportation Impacts Analysis: Impact on the state’s right of way and transportation infrastructure;
- Regulatory Scoping: Survey of needed approvals and agreements;
- Fatal Flaw Review: Review for engineering infeasibility.
After the CFS, depending on potential impacts to transportation facilities or plans, the project is then routed into one of two processes. If Caltrans determines there are no potential impacts, then the project is routed into a “Simplified Process for Caltrans Review and Oversight.” If, however the agency determines there may be potential impacts, then the project is routed to its “Typical Caltrans Process per Development Procedures Manual (PDPM).”
The simplified process, also referred to by Caltrans as the “Cap Oversight Process” (COP) can be conducted either by the project sponsor’s consultant in coordination with Caltrans’s Intergovernmental Review unit (IGR) or by Caltrans staff on a cost recovery basis (i.e. project sponsor is billed). The COP consists of the following stages:
- Environmental Evaluation: Distinguished from environmental review of the full project (under CEQA – California’s environmental review law), this evaluation considers only environmental impacts within the ROW. Caltrans uses its Standard Environmental Reference (SER).
- Preliminary Design Review.
- Agreements: Airspace Lease and Maintenance Agreements are negotiated and signed.
- Encroachment Permit: Caltrans entitlement of project comes in the form of an encroachment permit, which it grants only after finalization of design specifications, environmental evaluation, staging and traffic plans, airspace lease, and maintenance agreement.
- Construction Oversight: Before construction, project sponsor and Caltrans must enter a construction oversight agreement. Caltrans will perform inspections to insure compliance with approved plans and the project sponsor must submit all planned construction activities to Caltrans for review concerning impact on traffic, including staging plans, traffic plans, and schedules.
The full process, also referred to by Caltrans as the “Transportation Project Process” is the process set forth in its Project Development Procedure Manual (PDPM) for “for developing State highway improvement projects.” It is triggered if, during the CFS, Caltrans determines the project has potential impacts on transportation. This process involves a higher degree of agency involvement in the design and oversight of the project and includes the following stages:
- Project Initiation Document (PID). Often referred to as a Project Study Report, it is a detailed analyses of all physical aspects of the project, from purpose and need, to alternatives, to impacts, to design and construction, identification of necessary agreements and documents.
- Formal Project Studies: Engineering, Environmental (re highway operations), Draft Environmental Impact Review (CEQA impacts, mitigation, preferred alternative), and Draft Project Report (compares alternative designs ±30% level)
- Final EIR/EIS and Final Project Report (selected alternative full description).
- ROW certification: This stage ensures that project sponsor has secured all necessary rights of way, property, and agreements prior to issuance of Encroachment Permit.
- Encroachment Permit: Same as COP process.
- Construction Oversight: Same as COP process.
As previously mentioned, some states have additional useful materials. For example, the California DOT (Caltrans) is developing a “Freeway Cap Best Practices Guide,” which was still in draft form at the time of this writing, albeit available online.
Some level of environmental review will be a part of any highway airspace project. A general understanding of the environmental review regulatory process is a must for a project proponent. An experienced consultant is essential to shepherd the project through the process. Thus, an in-depth review of the regulations is beyond the scope of this manual. However, certain issues will be of keen interest to project proponents. For example:
- How long will it take?
- How much money will it cost? ($250,000 to $2,000,000 +)
- How to do it?
- What laws and processes come into play?
- When and how is environmental review compliance initiated?
- Are there are any streamlining opportunities?
Most highway projects will be required to go through the environmental review process set forth by the National Environmental Policy Act (NEPA). Additionally, many states have their own environmental review laws and processes. Additionally, projects will also need go through some level of review for potential contaminants on the land at issue under the Comprehensive Environmental Review Compensation and Liability Act (CERCLA aka the “Superfund” law). On top of that, the SDOT may have its own review requirements (e.g., Caltrans’s Project Study Report) It is often possible to at least partially combine these overlapping processes, particularly with respect to NEPA and the state environmental review, into a single environmental review document and that the major environmental documents are prepared to satisfy both state and federal law.
National Environmental Policy Act (NEPA)
The National Environmental Policy Act (NEPA) is invoked by major federal actions, which could impact the environment. Environmental review is also invoked by disposal agreements, ROW use agreements, and leasing actions involving any highway “that has been funded under title 23.” However, NEPA does not dictate an outcome. Its purpose is primarily disclosure, public notice, and participation.
Prior to committing to the project, NEPA requires a thorough review and analysis of potential environmental impacts. Agencies must prepare an environmental impact statement (EIS) on a major action if the action “may” or “will” have a significant impact on the environment. The EIS must identify the action, alternatives, environmental effects, and mitigation.
Major federal actions include actions by the federal government, on federal land, involving federal funding, or requiring federal permits (this includes private developments). Agencies must prepare an environmental impact statement (EIS) on a major action if the action “may” or “will” have a significant impact on the environment.
However, not every action requires an EIS. Alternative documents, where impacts are unlikely, include a Categorical Exclusion (CE) or an Environmental Assessment (EA).
Actions which neither individually nor cumulatively impact the environment may receive a CE. This determination is guided by the following general questions:
- Does the action have a significant effect on the quality of the human environment?
- Are there unresolved conflicts concerning alternative uses of available resources?
An EA is prepared when it is not clear whether an EIS is needed. This circumstance arises for potentially major actions. An EA will determine one of two courses: a Finding of No Significant Impact (FONSI) or an EIS. (An EA shouldn’t be confused with a Phase 1 Environmental Site Assessment (ESA), which relates to the requirements of CERCLA. However, an ESA can be part of the EA.) An EA process should include any state and local environmental review requirements.
Drafting an EA typically takes between 1 – 3 months, with agency review taking another 1 – 2 months. If the EA supports it, the relevant agency will issue a draft FONSI. The public and other agencies must be given at least 15 days for review and comment. The project sponsor must then respond to any comments identifying adverse impacts, mitigate the impacts or choose a project alternative. If the agency to determines that there are no significant unmitigated impacts, it may issue a final FONSI.
Source, U.S. Dept. of Energy
Environmental Impact Statement
If there is a determination that significant environmental effects may or will occur, the state department of transportation, FHWA, or other project sponsor must begin the process of preparing an EIS. The EIS process is completed in the following order:
- Notice of Intent (NOI)
- Draft EIS
- Final EIS
- Record of decision (ROD).
Between the draft and final EIS, the project sponsor considers and responds to all substantive comments received on the draft EIS.
To start, the project sponsor publishes a Notice of Intent to Prepare an Environmental Impact Statement (NOI). According to the U.S. Dept. of Energy’s Citizens Guide to NEPA:
The NOI provides a brief description of the proposed action and possible alternatives. It also describes the agency’s proposed scoping process, including any meetings and how the public can get involved. The NOI will also contain an agency point of contact who can answer questions about the proposed action and the NEPA process.
After receiving input on the scope of the EIS, the project sponsor prepares and publishes a draft EIS. Again, the sponsor receives and responds to comments. The review and comment period must be at least 45 days. Thereafter, the sponsor publishes the Final EIS, which includes responses to the comments to the draft EIS. After publication of the Final EIS, there is a waiting period of 30 days before the reviewing agency can make a decision.
The NEPA environmental review includes both statutory and practical time periods. A two year period, from inception of review to a decision, is not uncommon. The Army Core of Engineers has published an excellent spreadsheet which provides a timeline and detail regarding the NEPA process, included in Appendix D.
Contaminated Sites, Pollutants, Assessment, Cleanup, and Management
The processes for complying with laws and regulations concerning contaminated sites and the generation of pollutants from the project is typically integrated with environmental review, approval, and implementation of the project. Unless extensive cleanup or management is indicated, compliance will not necessarily increase the time indicated for approval. Detailed descriptions of these laws are beyond the scope of this book. However, since most freeway cap projects will be in urban settings, where site contamination and pollution is most prevalent, these laws will be part of the site evaluation and project approval processes.
The main federal law covering sites contaminated with hazardous waste and their cleanup is the Comprehensive Environmental Review, Compensation and Liability Act (CERCLA aka Superfund Law).
CERCLA has the purpose of identifying and cleaning up sites that have been contaminated with dangerous chemicals or other wastes. Funding of clean-ups is accomplished by identifying Potentially Responsible Parties (PRPs) and through the use of government funding – the “Superfund.” CERCLA begins with an Environmental Site Assessment (ESA). The first step of an ESA is a Preliminary Assessment and Site Inspection also known as a Phase I report. The Phase I involves research of the history of the site and it’s uses, as well as a visual inspection. Usually there is no sampling or soil testing in a Phase I. If the Phase I warrants further study, a Phase II study is conducted. Phase II will involve sampling and testing. Based on the foregoing, the project may either go forward without cleanup or a plan for cleanup must be developed and implemented before construction. If cleanup / remediation is indicated, the project sponsor or PRP must report the site for inclusion in a federal database. It must also study alternatives and feasibility, propose a cleanup plan, receive public comment, and finally pursue approval from the EPA.
Construction Sourced Pollution:
The Resource Conservation and Recovery Act (RCRA) is directed at managing solid and hazardous waste at sites that are currently in use. For freeway caps, it is most likely to pertain to demolition and construction activities. Like CERCLA, the RCRA moves from site assessment to a management plan to public comment and finally to approval.
Exposure to Freeway Auto Tailpipe Emissions:
The air pollution implications of proximity to high traffic roadways are attracting increasing attention. In particular, the concentration of ultra-fine particulate (UFP) pollution is closely related to proximity to high traffic roadways. UFP pollution has been associated with heart disease and cognitive impairment. To date however, most air pollution regulations pertain to addressing the source of the pollutants (e.g. vehicles and factories), or filtering/ventilating tunnels for the benefit of auto occupants, rather than restricting building in proximity to the source. Nevertheless, freeway cap projects are likely to face increasing scrutiny regarding the air pollution exposure of persons on or near the freeway caps from auto tail pipe emissions from the cars traveling underneath. This may be a short-lived concern if electric vehicles begin to significantly replace internal combustion engine vehicles. In the interim, the potential for elevated exposure to tailpipe emissions must be addressed, particularly in freeway cap projects that will host buildings in which people work or reside. For example, the Capitol Crossing project, which contains both residential and commercial buildings, was required to include “Eco-Chimneys” to vent and clean auto exhaust emissions. Alternatives for venting and filtering tailpipe emissions is discussed in Chapter 7.
State Environmental Laws and Procedures:
Many states have laws similar to NEPA, which can extend to projects not covered by NEPA. They can also apply alongside of NEPA. Commonly, environmental documents for NEPA can be combined with the analogous state environmental document.
A list of states with NEPA-like laws, along with additional information about those laws can be seen Appendix E These state laws have different scopes and rules. For example, some states apply their NEPA-like laws only to actions of the state. Others include actions of municipalities including discretionary permitting actions to approve private projects. Additionally, check for exemptions or streamlined processes applicable to certain types of projects. For example, California has streamlined review for certain large projects (in excess of $100 million) it calls “Environmental Leadership Projects.”  (See Appendix F)
 Interstate Highway System. (n.d.). In Wikipedia. Retrieved Jan. 23, 2018 from https://en.wikipedia.org/wiki/Interstate_Highway_System
 National Highway System (United States). (n.d.). In Wikipedia. Retrieved Jan. 23, 2018 from https://en.wikipedia.org/wiki/National_Highway_System_(United_States)
 23 CFR 1.23 – Rights-of-way.
 Interstate Highway System, supra, Wikipedia
 National Highway System, supra, Wikipedia
 U.S.D.O.T. – F.H.W.A, National Highway System, Retrieved on Nov. 1, 2017 from https://www.fhwa.dot.gov/planning/national_highway_system/
 U.S.D.O.T. – F.H.W.A, National Highway System, Intermodal Connectors. Retrieved on May 9, 2018 from https://www.fhwa.dot.gov/planning/national_highway_system/intermodal_connectors/
 California Dept. of Transportation, Right of Way Manual, Ch. 15, Sec. 15.06.11.03 “Final Approval.” Retrieved on Nov. 2, 2017 from http://www.dot.ca.gov/hq/row/rowman/manual/
 Id. at Sec. 15.06.13.00 FHWA Approval.
 FHWA, Right-of-Way Program Administration – State Right-of-Way Manuals, Retrieved on Nov. 2, 2017 from: https://www.fhwa.dot.gov/real_estate/right-of-way/program_administration/srowm.cfm
 Many of the state manuals still refer to sections of the Code of Federal Regulations (CFR) Title 23 Subchapter H, as it existed in before 2000, particularly 23 CFR 713 concerning the management of airspace. However, in 2000, Subchapter H was amended and reorganized. Part 713 no longer exists, and the topics therein have been relocated (64 FR 71284, Vol. 64, No. 244, Dec. 21, 1999) as follows:
713, subpart A (713.101-713.103) → 710.101-710.103.
713, subpart B (713.201-713.205) → 710.405.
713, subpart C (713.301-713.308) → 710.407-710.409.
 CalTrans (2017), Freeway Best Practices Guide, Final Draft; Retrieved on April 4, 2018 from http://www.dot.ca.gov/hq/tpp/grant_files/final-products/11_FwyCapBestPracticesGuideFinalDraft_03122017_Watermark.pdf
 Title 23 CFR § 710.403(d)
 Colorado Dept. of Transportation, Right of Way Manual, Chapter 7 – Property Management (May 20, 2016), 7.2.9 – Disposal or Lease at less than Fair Market Value. Retrieved Nov. 2, 2017 from https://www.codot.gov/business/manuals/right-of-way
 Airspace Guidelines to 23 CFR 710.405 – 710.407 (2010), 710.405_10, Retrieved on Nov. 13, 2017 from http://www.fhwa.dot.gov/real_estate/right-of-way/corridor_management/airspace_guidelines.cfm
 Additionally, as previously noted, Title 23 CFR § 710.405(b)(4) requires that such agreements “[e]stablish terms for revocation of the ROW use agreement and removal of improvements at no cost to the FHWA.” The Airspace Guidelines for ROW goes on to explain that use agreements states that each agreement should contain provisions to:
“Revoke the agreement in the event that the airspace facility ceases to be used or is abandoned, or becomes necessary for highway purposes” and
“[A]ssure full understanding that the airspace user will not qualify for relocation benefits under the Uniform Act.”
 The manuals and publications can be found on the FHWA’s “Bridges & Structures” page (https://www.fhwa.dot.gov/bridge) under any one of the topical links.
 As mentioned, California is developing a “Freeway Cap Best Practices Guide.” Retrieved on April 4, 2018 from http://www.dot.ca.gov/hq/tpp/grant_files/final-products/11_FwyCapBestPracticesGuideFinalDraft_03122017_Watermark.pdf
 See California Department of Transportation – Standard Environmental Reference, Retrieved on Dec. 14, 2017 from http://www.dot.ca.gov/ser/
 Caltrans, Project Development Procedure Manual, Retrieved on Dec. 14, 2017 from http://www.dot.ca.gov/design/manuals/pdpm.html
 Freeway Best Practices Guide, Final Draft, supra, http://www.dot.ca.gov/hq/tpp/grant_files/final-products/11_FwyCapBestPracticesGuideFinalDraft_03122017_Watermark.pdf
 23 CFR 710.403(d) and 23 CFR 771
 Hayes, D.J. & Hourihan, J.A. (9/1/1985), NEPA Requirements for Private Projects, Boston College Environmental Affairs Law Review, Vol. 13, Issue 1 Art. 3, 61-62.
 U.S. Bureau of Reclamation, National Environmental Policy Act National Environmental Policy Act
of 1969 (NEPA) of 1969 (NEPA), Retrieved from https://www.usbr.gov/gp/ecao/slideshow.pdf
 U.S. Health Resources & Services Administration, FAQ: NEPA Environmental Assessments, Retrieved from https://bphc.hrsa.gov/policiesregulations/nepa.pdf
 Council on Environmental Quality, Executive Office of The President of the U.S. (2007). The Citizen’s Guide to the National Environmental Policy Act, p.8
 The Citizen’s Guide to the National Environmental Policy Act, supra, p.13
 U.S. Environmental Protection Agency, National Environmental Policy Act Review Process, Retrieved on Dec. 23 from https://www.epa.gov/nepa/national-environmental-policy-act-review-process
 Adams, William. What is a safe distance to live or work near high auto emission roads? UrbDeZine (2015) Retrieved from https://sandiego.urbdezine.com/2015/05/28/what-is-a-safe-distance-to-live-or-work-near-high-auto-emission-roads/
 Council on Environmental Quality, State NEPA Contacts, (June 22, 2013): Retrieved from https://energy.gov/nepa/downloads/states-nepa-environmental-planning-requirements
 Montana, Improving the Montana Environmental Policy Act (MEPA) Process – Senate Joint Resolution No. 18: Report to the 57th Legislature of the State of Montana, Chapter 5 (How Does MEPA Compare With Other State Environmental Policy Acts?), retrieved from http://leg.mt.gov/css/publications/environmental/2000mepa_report/mepa_tofc.asp
 Cho, Juliet H. (2011), California Governor Signs AB 900 Streamlining CEQA Challenges, California Environmental Law (Stoel Rives LLP), Retrieved on 12/14/2017 from https://www.californiaenvironmentallawblog.com/ceqa/california-governor-signs-ab-900-streamlining-ceqa-challenges/
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