Transit-oriented development (TOD) is a planning strategy that promotes high density, mixed-use (residential and commercial) development centered around public transportation services. Focusing development in the vicinity of public transit increases potential ridership and fare revenue while also generating less traffic and household transportation costs for the new development. While TOD can improve access and mobility, it can also increase housing prices, which pose the risk of gentrification. As a result, some governments have turned to equitable TOD (ETOD) as a strategy to ensure a more inclusive environment around transit developments, and affordable housing is a key element in ETOD strategies.

This is the third installment in Eno’s continuing series examining how metropolitan areas across the country are approaching TOD work, including how agencies coordinate across housing, land use, and transportation, what tools they use, and what constraints they encounter on affordable housing and transit policy.

This Week: The Bay Area and BART

Issues in Housing Affordability

The San Francisco metropolitan area, commonly known as the Bay Area, is the second largest metropolitan area in California, and faces a challenging housing crisis. The population has grown over the past 60 years, and the region grew 6 percent between 2010 and 2020, but the supply of housing has failed to keep up with the Bay Area’s growing population. In addition to housing supply, housing affordability is a serious issue for area residents, according to a 2025 poll from Joint Venture Silicon Valley.

Data from the National Association of Realtors and National Low Income Housing Coalition support the fact that the Bay Area faces housing affordability challenges. According to the National Association of Realtors’ Housing Affordability Index, the Bay Area is the least affordable among ten selected metropolitan areas. The ten selected metro areas are shown in Table 1 below along with their Housing Affordability Index score. The index measures whether the typical family in each region earns enough income to qualify for a mortgage loan on a typical home. An index above 100 signifies that a family earning the median income has more than enough income to qualify for a mortgage loan on a median-priced single-family home, assuming a 20 percent down payment. The index for the Bay Area in 2022 was 47, well below the threshold for affordability. In other words, out of these metro areas, the typical family in the Bay Area is the least likely to earn enough income to qualify for a mortgage on a typical home.

Table 1. Housing Affordability Index

The rental market in the Bay Area faces a similar challenge in affordability. According to 2025 data from the National Low Income Housing Coalition, the Bay Area region has 44 affordable and available units per 100 eligible households (those who earn at or below 50 percent of area median income). Across the U.S., there are an average of 53 affordable and available units per 100 households at that income level.

TOD at BART

The San Francisco Bay Area Rapid Transit District (BART) is the heavy rail transit provider for the San Francisco Bay Area, serving the area since 1972. The BART system was primarily designed so that suburban residents could park their cars at stations, and then take a train to major employment centers (such as those in Oakland, San Francisco, and Berkeley.) BART currently owns and operates more than 47,000 parking spaces at 36 stations.

While BART’s primary function is to provide public transit in the Bay Area, the agency established a TOD program in 1990s, recognizing the value of development around transit stations beyond surface parking. The TOD program was created with the goal of attracting more riders and promoting economic development.

Since 1993, BART has completed 22 TOD projects with 4,232 residential units (of which 1,298 are affordable) and about 875,000 square feet of commercial space. The agency currently has eight projects in the planning or pre-development stages and owns more than 250 acres around 27 of its train stations with development potential. Although most of the agency’s TOD focus relates to land that it owns, it also has a station area planning team that works with municipalities to influence local zoning so that local zoning ordinances are transit supportive. BART’s legislative team also tracks and engages in state-level legislative efforts aimed at reducing barriers to developing housing and other transit-oriented uses around transit stations.

Along with ridership and economic growth goals, BART has included housing goals in its TOD work, addressing both housing supply and affordability challenges. In 2016, the BART Board adopted an ambitious goal of completing 20,000 residential units and 4.5 million square feet of commercial space on BART property by 2040. The agency’s goal is for 35 percent of the units across the TOD portfolio to be affordable.

Elements of BART’s TOD Program

BART’s TOD Policy and Guidelines

BART’s TOD policy acts as the foundation for the agency’s development work. The agency adopted a TOD policy, in 2016, incorporating its previous TOD goals, and further amended the policy in 2020. The policy’s six goals include increasing ridership, encouraging non-auto transportation choices, and linking housing affordability with access to opportunity. The agency also lays out several strategies to support the implementation of its TOD program including:

• Developing a four-year plan that lays out planning, community engagement, and funding efforts towards TOD projects.
• Supporting local jurisdictions in developing plans and policies that include TOD elements.
• Ensuring that TOD projects increase BART ridership overall and encourage reverse-commute, off-peak, and non-work trips.

The TOD policy also incorporates BART’s affordable housing policy, which states that at least 20 percent of the housing units at a BART TOD should be affordable. The policy does not identify a certain income that is considered affordable, although it does state that there shall be a “priority on residential units made available to very low (less than 50 percent AMI) and low (51 to 80 percent AMI) income households.” The affordable housing policy further calls for 35 percent of all residential units across BART’s TOD portfolio to be affordable. BART uses incentives to achieve the TOD policy goals, allowing up to a 60 percent discount on ground leases for projects that exceed the 35% affordable housing goal.

Alongside its TOD and Affordable Housing policies, BART issued a TOD Guidelines document in 2017 to provide greater clarity about the agency’s expectations both on its property and within the larger station area. The purpose of the guidelines document is to:

• Disseminate information about BART’s TOD program to developers, local governments, and staff.
• Lay out a road map for defining, evaluating, selecting, and constructing TOD projects.
• Identify roles and responsibilities of BART staff, local governments, and developers.
• Offer guidance in developing station area plans.

Prioritizing Sites

Many cities and counties have identified BART-owned or -operated land as potential TOD sites. However, due to capacity and funding constraints, only a limited number of projects can be advanced for development each year. The agency prioritizes development proposals for TOD in localities that have an adopted plan and zoning allowing for transit supportive land uses, where infrastructure barriers are minimal, where data indicates market readiness, and where sites can generate significant development.

Parking and Land Use

For BART station areas, BART encourages local governments to adopt transit supportive land use regulations that enable a minimum net density of 75 units per acre and have no minimum parking requirements. In the TOD Guidelines, BART adopted a target that by 2025, the average parking at developments will not exceed 0.9 spaces per residential unit, and 1.6 spaces per 1,000 square feet of commercial space. The agency uses a parking replacement model to quantify the ridership and revenue impacts of different TOD scenarios. The agency notes that building TOD on BART property will bring in new riders, but the increase may be offset if the number of parking spaces is reduced, and some drivers stop taking BART. Additional concerns over reduced parking are the ability for some riders to access the station who primarily drive and the potential for spillover parking in surrounding neighborhoods.

Revenue from parking is relatively modest with the agency charging previously charging $3 per day to park at most BART stations, not accounting for the cost of operating, enforcing and maintaining the parking facilities. In FY 2025, BART generated $244 million in fare revenue and $18 million in parking revenue. In 2026, the agency raised the parking fee to $3.40 per day at most BART stations, which will raise revenue generated from parking fees.

At some TOD sites, ground floor retail has been required, but retail vacancy rates have been high. To avoid that problem, BART has shifted to allowing more flexibility relating to ground floor uses (that is, not requiring a set amount or supporting community serving uses such as after school programs).

TOD Benefits to Ridership

BART reported that development within a half mile of its stations is crucial for increasing ridership because the frequency of residents, employees, and visitors using transit for a variety of trip purposes increases as the distance to that station decreases. One pre-pandemic study of Bay Area transportation and land use found that TOD residents commute by transit five times more than the average worker in the same city and TOD office workers commute by transit 3.5 times more than workers in the surrounding region. Another study found that TOD residents living within 0.25 miles of a BART station use transit for work trips twice as often as those living one to two miles away from BART stations.

State legislation regarding TOD and affordable housing

Housing Elements Law

The State of California requires all cities and counties to adopt a housing element as part of a general plan to identify how they will accommodate projected housing needs. The housing element process identifies housing needs across income levels, and identifies local strategies to respond to those needs. State funding programs for transportation, infrastructure, and housing often require or consider a local jurisdiction’s compliance with this requirement.

Baseline Zoning Standards

In 2018, California’s state legislature passed Assembly Bill 2923 enabling BART to establish transit-oriented zoning standards on BART owned land near BART stations in San Francisco, Alameda, and Contra Costa counties. These standards include building heights, residential densities, floor to area ratios, parking maximums, and transportation demand management requirements. Local jurisdictions were required to adopt local zoning changes to conform to BART’s zoning standards within two years of BART developing them. If local jurisdictions did not adopt conforming to the zoning, the BART standards would apply. This law currently sunsets on January 1, 2029.

In October 2025, California Governor Gavin Newsome signed into law SB 79, which establishes statewide TOD zoning standards relating to height, density, floor-area-ratio (FAR) for land in proximity to transit stations that see more than 48 trains per day. Housing projects are eligible for the increased density, height, and FAR standards if they are within one-half mile of a station, with additional heigh, density, and FAR benefits projects within one-quarter mile of a station.

Barriers to TOD and Affordable Housing

Market conditions

High interest rates and high construction costs are creating unfavorable conditions for development and land transactions associated with the construction of both market rate and affordable housing. Along with housing, office buildings can be a key element of TOD projects. But demand for new office construction in the Bay Area has declined substantially since 2019 due to changing travel patterns and the greater prevalence of work from home.

Balancing priorities

It can be challenging for a transit agency to balance priorities including providing access for customers, generating maximum revenue from leasing land, advancing affordable housing, and labor standards, all while serving as a public transit provider for the region.

Key Lessons

Planning Efforts

• Transit agencies need to document requirements that developers must comply with when designing, constructing, and operating TOD projects. For example, if a parking area has an electric substation or a bus facility, the transit agency needs to provide clear expectations on required clearance buffers and maintenance access for the development team to integrate into site planning and construction phasing.
• Clear TOD guidelines from a transit agency provide clarity to local governments and developers about its expectations both on its property and within the larger station area.

Gathering internal and External Support

• It is important to get multi-disciplinary support within transit agencies and municipalities to support projects. That includes departments within cities (e.g., engineering, emergency services) and transit agencies that serve stations (operations, planning, customer access, maintenance). When they are not aligned, projects are more difficult to move along.
• Having the support of local political leadership with TOD policies and projects is critical. The transit agency should make sure that political leaders (transit agency board members, mayors, city council members, and even state legislators) are aware of projects, their impacts, funding needs, and key milestones.

Taking Advantage of an affordable housing-friendly environment

• Because of the region’s housing crisis, the general public and elected officials have become more supportive of affordable housing. That can be seen in AB 2923, local housing elements, and more organized community voices that have led to a YIMBY (Yes In My Back Yard) movement.
• Bond measures and housing trust funds have helped fund affordable housing projects. For example, Alameda County voters in 2016 approved a referendum for the county to issue up to $580 million in bonds to support the creation of an expected 3,800 affordable homes. Also, 30 California cities (including San Francisco, Berkeley, and Oakland) have established housing trust funds that can pay for the preservation and rehabilitation of existing housing, land acquisition, new construction, and rental subsidies, but not TOD development.