Estimating the Size of Parking Spots

We pull into them with regularity, some with ease, some with our breath held as we squeeze our car in. It sometimes feels like victory to get into a spot, then get out and suck in your belly as you slide out, especially if it has been a long hunt for that open spot. The specialty profession of parking design revolves around the complex puzzle of fitting cars in a limited space. When we do site testing as urban designers, we follow rules of thumb like the ones below to help us estimate the physical size of the parking field or structure.
  • For a typical parking space, surface or structured, a spot can range between 320 sf to 430 sf gross per space, including aisles, corners, columns, landscaping, disabled, mechanical, ticketing, and more.
  • 430 sf/space is for surface parking (no structure) and odd shaped sites with generous landscaping. This maximum size works out to about 100 spaces per acre (43,560 sf/acre / 430 sf/space = about 100 spaces/acre).
  • 320 sf/space is for a large, efficient parking structure with clear span, double loaded, 90 degree parking, and parking around the entire perimeter.
  • A relatively good number for standalone parking structure is 350 sf/space.
  • For surface parking and parking structure, with building(s) above a useful size to estimate with is 400 sf/space.
  • These parking spaces assume that the spaces are typically 90 degrees, 9 feet wide by 18 feet long with aisles of at least 24 feet wide. That would make a double loaded 90 degree parking bay 60 feet wide clear.
These numbers help us figure out how much parking can we fit onto the site. How much parking is actually needed? That is another hot topic entirely!