Can San Francisco Build Housing That Eases Traffic?

Can a new apartment building take vehicles off the road?

Not according to 20th-century planning logic, wherein more residents means more cars. That explains why many cities require developers to build boatloads of residential parking, even in dense neighborhoods with good transit. But such parking minimums often have counterproductive effects: Congestion gets worse, and rents get higher.

San Francisco certainly knows a thing about that: The city is currently dealing with a triple-whammy of traffic woes, an overburdened transit system, and jaw-dropping housing costs. (How brutally expensive is it to live there? Lately, wooden sleep-pods are the best-looking affordable solution.) But Bay Area planners believe that new buildings can solve two problems at once: 1) accommodate more people in a city bursting at its seams, and 2) actively ease overstressed and congested roads.

The hope is to establish a citywide “transportation demand management” program, requiring developers of new buildings to incorporate design features that cut down on vehicle-miles traveled. Officials from the San Francisco Planning Department, MTA, and County Transportation Authority have developed a 26-item menu of research-backed TDM measures, each of which comes with a certain amount of points. Every new development project would be assigned a site-specific point target, and to reach it, developers would choose their blend of VMT-reducing features.

On the lower end of the point scale are things like offering a fleet of bicycles and real-time transit information displays. At the the upper end, options include subsidized transit passes, running commuter shuttles, and slashing onsite parking.

Boulder, Cambridge, Santa Monica, and other cities also have TDM ordinances. But their policies have mainly applied to commercial developments and office spaces. The San Francisco code would apply to all new buildings of a certain size (10 or more units for residential, upwards of 10,000 square feet for commercial or institutional spaces). And it makes encouraging transit a priority, rather than an afterthought, for developers.

A few TDM measures, such as bike lockers, showers, and parking lot fees, were already sprinkled into the city planning code. But senior planner Wade Wietgrefe says that stuff generally only made it into projects on a voluntary basis, or as a mitigation following an environmental review. Now, developers will have to incorporate driving-reduction efforts before their projects get the green light from City Hall. “They’re going to decide, ‘Do I want to provide 50 parking spaces if I need 20 points of TDM measures? Or do I want to provide 25 parking spaces because that'll get me closer?’” says Wietgrefe. “So they get to weigh the costs and benefits of these features upfront and integrate that into the project from the beginning.”  

Some of the measures are a bit more nuanced than hacking down parking spaces. For example, a developer who builds a mixed-use complex with healthy grocery options in an otherwise underserved neighborhood would get awarded a higher TDM score. Carli Paine, a TDM manager with the SFMTA, also came up with some ways developers can help keep young families out of personal vehicles. “I know many parents of young kids who’ve been challenged by going from a car-free life to feeling the pressure to own a car,” she says. “Car-share doesn’t always work for them, because if you have [child] car seats, where do you store those? Especially in a small apartment, are you going to have a whole closet for that?” So buildings can earn points by running a car-seat check-out program located near car-share parking—and even more if they offer onsite daycare services.

Passed unanimously by the city planning commission in August, and now awaiting the word of San Francisco’s board of supervisors, the ordinance represents the final piece of the city’s “Transportation Sustainability Program,” a three-pronged game-plan that tries to balance much-needed growth with improved mobility. The first part was a new building fee, designed to offset the impact new residential development has on existing transit systems. The second was to change how those very impacts are evaluated under California state law, from a very car-centric measure of driver delay to the more transit-friendly metric of vehicle-miles traveled. Both of those actions have been accomplished. Now all that’s left is for San Francisco to start plugging in the design of new developments in its grand scheme to prioritize transit. Developers have been been fairly supportive so far; "Many of them already see the writing on wall, in terms of less parking as the future of transportation," says Wietgrefe.

But perhaps the most intriguing part of the plan is how it’ll be evaluated once put into action. The ordinance will effectively turn new buildings into transportation-demand laboratories. After the city signs off on a development’s blend of TDM options, officials will regularly check up on how effective the plan is in reality, surveying residents and workers about how they’re getting around, and counting trips for different transportation modes. Besides revealing how transit-friendly one building is compared to another, this site-specific data should also help ground loftier, city-wide sustainability targets for things like VMT, population growth, and road capacity.

“Over time, we could be able to say, OK, in high density, transit-rich neighborhoods, a free bike-share program could get you an X percent reduction in VMT, versus Y percent in other neighborhoods,” says Michael Schwartz, the principal transportation planner with the SFCTA. “Once we have more development coming in, we’ll have a good sense of what pressure that puts on our networks, what kind of transit ridership we’ll see, and whether we need service upgrades.”

Estimating these sorts of impacts has long been an exercise in generalization, says Schwartz; he calls the kind of data that San Francisco wants to extract from its TDM ordinance is the “holy grail” of transportation planning. It moves from assumptions about how people move—exemplified by those parking requirements of yore—to research-backed goals: a shift very much in line with national "smart city" trends (and also with the Bay Area’s tech-infused urban culture). Schwartz and his colleagues hope other cities can make use of the TDM results to do their own planning or develop programs modeled after the plan. San Francisco might be the poster child for a national affordable housing crisis, but it could also offer a blueprint for fixing at least one of the problems stemming from it.

“San Francisco needs to grow to meet affordability and diversity goals,” says Schwartz. “How do we do it in a way that also leads to better transportation? For the first time, we’re thinking that through in a comprehensive way.”