Study Finds Off-Street Residential Parking Overbuilt

 New research by the Metropolitan Area Planning Council (MAPC) shows most of the communities in Metro Boston have built more residential off-street parking than is needed or utilized, with nearly 30 percent sitting vacant at peak demand time, contributing to higher construction costs, higher rents, fewer housing units, and less space for parks and greenery.

The study, conducted during “peak parking” times – overnight on weeknights, at nearly 200 multifamily developments across 14 cities and towns – showed that local zoning rules often mandate excessive parking even as many homeowners and renters do not own vehicles and instead prefer public transit, biking, car share, and ride-hailing services to get around.

“Cities and towns shape the region’s future through their local land use regulations, and ought to implement parking requirements that align with actual use and demand,” said Marc Draisen, Executive Director of MAPC. “During this research, we witnessed oversupply of parking in every surveyed community. Reducing excess parking can encourage more housing units, at a lower rent or sales price. Aligning parking supply and demand at buildings near transit can also promote transit use over driving, which in turn alleviates congestion.”

To understand current trends in parking supply and demand at multifamily developments, MAPC collected off-street parking data for nearly 200 multifamily developments across 14 cities and towns in the Inner Core of Metro Boston, including Arlington, Boston, Cambridge, Chelsea, Everett, Malden, Medford, Melrose, Newton, Quincy, Revere, Somerville, Waltham, and Watertown. First, MAPC surveyed property managers to determine the amount and type of on-site parking provided for residents. MAPC staff then conducted in-person overnight parking counts to measure parking utilization during peak parking demand hours, when most people are asleep and the number of parked cars is expected to be highest.

Across the municipalities surveyed, MAPC found an average of one parking space supplied per unit. However, residents of the vast majority of the developments surveyed used less than one space per unit; the average demand for parking was only 0.73 spaces per household.

Overall, 30 percent of the 19,439 parking spaces counted overnight were empty, amounting to more than 41 acres of empty pavement. Put another way, this excess parking added an estimated $94.5 million in construction costs, or about $5,000 per housing unit in the study area.

In addition to increasing housing costs, building too much unnecessary parking reduces the amount of valuable land that could have been put to other uses, such as green space or bike storage.

In the study, MAPC dug deeper into the building characteristics of 25 sites in the survey to explore how building and neighborhood characteristics influenced parking demand, if at all. In doing so, MAPC found certain factors strongly affected parking demand: Nearby transit access, specifically the ability to get to jobs via public transportation; the percent of deed-restricted affordable units; and the amount of parking offered. In summary, the study found that supply was the single biggest predictor of demand, suggesting that the availability of parking is influencing behavior and attracting car-owning households.

“The more parking that is provided, the more likely it is that residents will use it,” said Draisen. “By reducing parking supply to align with demand and pursuing additional transportation demand management strategies to promote alternatives to driving, we can reduce the barrier that excess parking places on the development of transit-oriented, walkable, and diverse communities.”

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How can cities and towns adapt?

Some of the communities in the study area have already taken steps to tackle excess parking, allowing for more flexible parking requirements in some of their most walkable and transit-oriented districts. The findings from MAPC’s research, however, reveal that more work needs to be done. For cities and towns looking to alleviate the burdens of excess parking and to expand sustainable transportation options to residents, MAPCrecommends the following:

•Require fewer spaces (or none at all). Much of the oversupply MAPC observed stemmed from excessive parking requirements in the local zoning code. In Metro Boston, many developments are approved through a special permit process. During this process, developers often advocate for reducing parking beyond the minimums required through zoning, but confront resistance from neighbors. Every city and town can consider reducing their existing requirements, and, more importantly, can tailor those requirements to different types of development in different locations. Shared parking (daytime/nighttime) is one proven strategy for reducing parking construction while meeting community needs. In some cases, as San Francisco has just done, parking minimums can be eliminated entirely, and parking maximums established to prevent over-supply.

•Design transit-oriented developments for transit-oriented households. Abundant parking at developments meant to be transit-oriented is counter-productive. It attracts car owners, makes housing less affordable for car-free or car-limited households, and encourages residents to use cars for trips that could be made by transit, walking, or biking. New housing in areas with good transit connections should provide less than one space per unit so as to accommodate households with fewer vehicles. Bike storage, car sharing, transit subsidies, shuttles, and human-oriented design are also all key elements of transit-oriented development. 

•Don’t make people pay for what they don’t need. In many developments, housing and parking is a package deal. Car-free households have to pay for parking they don’t use, or are tempted to buy a car to make use of the space. Property owners should unbundle the rental costs for housing and parking so that residents can choose whether or not to rent a parking space. State and local regulators should encourage or require them to do so.  Furthermore, regulations and development approvals should be structured so that parking spaces not needed by building residents can be leased to neighbors, local employees, or commuters.

•Less parking, more affordable housing. Developments with more subsidized units require less parking than market-rate developments, and produce correspondingly fewer auto trips. Communities seeking to reduce traffic impacts of new development should require more affordable units and enable lower parking requirements in return. Because residents at affordable housing sites are demonstrated to have lower parking demand (and thus are more dependent on transit), we should not only build less parking at transit-oriented sites, but also including a larger share of affordable units in these projects.

•Affordable housing funders and developers can also take steps to align parking supply with demand, and save valuable public resources in so doing. State and local regulators should recognize this relationship between affordable housing and parking demand, and permit higher rates of affordable housing at transit-oriented sites with an understanding that the auto trip generation will be much lower than market rate housing.     

•Get ready for a parking marketplace. The increasing pressure on street parking, combined with excess parking in residential (and possibly commercial) developments and the rise of the sharing economy, sets the stage for an app-enabled marketplace in which residents and property owners can rent spaces on demand, for minutes or months  — think Airbnb for cars. Public agencies have the opportunity to set parameters and tax policy now, before this market has established itself and becomes resistant to regulation. Cities and towns can be leaders in this field until the Commonwealth acts. 

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