Could road diets have saved the lives of 28 pedestrians?

Walking in Seattle analyzed pedestrian fatality data^* from 2001 to 2009 and found that 28 of Seattle’s 90 fatal pedestrian collisions occurred on roads that may be eligible for a lane rechannelization.

A lane rechannelization, or road diet, involves re-striping the roadway, often to add bike lanes or reduce the number of lanes for motor vehicles, with the intent of improving safety by slowing vehicle speeds and shortening crosswalk distances.

Through usually controversial when proposed, 26 road diets have been successfully implemented in Seattle since the 1970s. Streets that have recently been rechannelized include Stone Way, Fauntleroy Way, Nickerson Street, and 125th Avenue. According to pro-pedestrian organization Feet First, “When [road diets are] done properly at appropriate locations, all users benefit.”

One benefit of a lane rechannelization is lowered speed. The road diet on Nickerson Street has dropped motor vehicle speeds from 40-44 mph to 34-37 mph. A pedestrian hit at 40 mph is about 85% likely to die; a pedestrian hit at 30 mph is about 40% likely to die.

Since the road diet on Stone Way, Seattle’s Department of Transportation reports that collisions on that street have dropped by 14%, injury collisions have dropped by 33%, and collisions with pedestrians have dropped a full 80%!

SDOT doesn’t have a specific road diet program, but “we have been using rechannelizations as part of our paving program or proactively as part of other work,” says spokesperson Rick Sheridan. A road diet is a relatively inexpensive and reversible way to compensate for shortcomings of the roadway design and “one tool to improve safety through traffic calming.”

SDOT considers a roadway eligible for a road diet if vehicles routinely exceed the speed limit, if there are a history of collisions on the roadway, and if the lanes can be reduced without significantly impacting the current travel volume. SDOT considers 25,000 vehicles per day as a maximum volume for a four-lane roadway to receive a lane rechannelization.

Walking in Seattle has applied the above criteria to the 104 pedestrian fatalities (a result of 90 collisions) that have occured from 2001-2009 to come up with a list of roads that could be eligible for changes to the roadway striping. We feel that 28 of these collision sites deserve further study by SDOT:

Many of these roads have four lanes of vehicle traffic and could have a center turn lane added, similar to other road diets. Some of these locations only have two lanes of traffic, like California Ave and Adrmiral Way, however the current lanes are wide and encourage higher speeds. By adding bike lanes and striping the parking lane, the main road space would be constrained and drivers would slow down.

While the city has been falsely accused of waging a “war on cars” through implementation of road diets, these statistics suggest that the city’s efforts have not been aggressive enough at reducing roadway fatalities.