Benchmark 1: Maximum parking spaces per unit

Depending on the location and place type, an eligible project needs to meet the benchmarks and outputs listed in Table 1 to achieve a GreenPlace certification.

Projects that substantially exceed the basic certification benchmarks receive platinum level recognition, according to standards listed in Table 3 at the end of this section.

Benchmark 1: Maximum parking spaces per unit

Parking availability is one of the most important factors determining how much traffic is generated from a development. A growing body of evidence demonstrates that it is the amount of available parking that generates demand for parking and vehicle use – rather than the other way around.6 7 8 Higher levels of car ownership and parking demand encouraged by parking availability lead to increased traffic, vehicle miles traveled, air pollution, and greenhouse gas emissions.

By avoiding excessive parking, a new development encourages residents to take full advantage of a site’s walkability, nearby services, and transit. New residents who don’t own cars or are willing to go carfree, are often self-selecting buildings with little or no parking but with great transit access and walkability. But if ample parking is provided, a building may attract those more predisposed to drive, generating more local traffic.

Recent studies show that demand for parking depends on three key variables – availability, attractiveness of alternatives to driving, and price.

We established parking maximum ranges for eligible projects by consulting with planners and developers in leading jurisdictions, reviewing recently built and approved projects, and assessing trends in parking ratios. Parking ratios vary across the region – with parking ratios in DC for newly developed and pipeline projects notably lower than those in other jurisdictions.

DC’s low parking rates can be attributed to a number of supportive factors. The walkable urban environment and wealth of transportation options in many neighborhoods in DC are important factors in reducing demand and encouraging developers to build less parking. DC’s parking minimums typically require 1 parking space for every 2 or 3 units, but DC’s zoning variance process has also enabled developers to build even fewer spaces or provide no on-site parking at all. Finally, beginning in September 2016, new zoning standards for multifamily development will reduce the requirement near transit to 1 space per 6 units.* 9 These low ratios are uncommon in the other inner

* After September 2016, DC’s zoning requirement for most multifamily residential construction will be 1 space per 3 units, unless the project is within one-half mile of a Metro station or one-quarter mile of a bus priority or streetcar corridor, in which case the requirement will be 1 space per 6 units.