A study conducted by Matt Darst at Conduent has taken a long hard look at the effects of demarcated and undemarcated, or “free flow” parking spaces, and reached some interesting conclusions.

 It has been established wisdom since 2002 that when individual parking spaces on a city block are left unstriped, more cars can actually fit on that block, since some spaces are used by compact cars and motorcycles, and every striped space must be large enough to accommodate a full-sized car. City officials have made estimates of a “1-1.5 spaces gained” per block.

 Darst and his team set out to test this hypothesis. They filmed representative Undemarcated blocks in multiple cities during daytime over a period of several weeks, then measured the number of cars parked there, and their distance between each other. The surprising finding was that Undemarcated spaces were actually significantly less efficient than demarcated streets. On blockfaces that would be able to contain 9 demarcated parking spaces according to standard size of 18 feet per demarcated space, 9 vehicles were observed parked there not once. 8 vehicles were parked there only 2% of the time, and even 7 vehicles were parked there 15% of the time.

 This lack of full occupancy in urban, in-demand parking areas seems to have two causes: 96.1% of the time, cars were parked inefficiently, such that fewer than 9 cars parked on the block left no 18 foot-long spaces for a 9th car. A secondary effect, based on studies of vehicle size and distance traveled to find parking, may be a perception effect.

 The perception effect refers to the fact that even when there 18 or more feet of undemarcated space exists between 2 cars, if a driver does not perceive that they have enough room to park there, they won’t park there. Demarcation makes it clear to all drivers if a space is available, otherwise uncertainty and doubt can creep in.

 As a result of these factors, motorists are more likely to find an available parking space in demarcated environments than Undemarcated similar environments. Cities looking to maximize the use of their parking space need to consider the value of striping. In the future we’ll look into other results from this study, comparing the benefits of Single Space and Multi Space meters.