City Hall

Preliminary Data Show Nickerson Road Diet Is Working

By Erica C. Barnett February 2, 2011

Data collected by the city of Seattle three months after implementing the controversial "road diet" on Nickerson (reducing the street from four lanes to two travel lanes and a turning lane, plus a bike lane on each side) show that the same number of cars have been able to use the street, and that traffic has slowed somewhat, since the city restriped the road.

SDOT traffic manager Eric Widstrand says the data are still preliminary; the city will continue to do traffic counts through the rest of 2011 and release a full report after the end of the year. However, so far, the study shows that car and freight traffic haven't been harmed by the lane reduction, and that traffic has slowed to be somewhat closer to the 30-mph speed limit on the road.

"Capacity has not decreased," Widstrand says. "We're still able to accommodate" between 15,000 and 18,000 vehicles a day.

The typical speed of traffic on Nickerson, meanwhile, has gone down from 40-44 mph to 34-37 mph. "We aren't slowing anyone down excessively," Widstrand says. The new speeds remain higher than the 30 mph speed limit, but are still safer for cyclists and pedestrians. A pedestrian hit at 40 mph is about 85 percent likely to die; a pedestrian hit at 30 mph is about 40 percent likely to be killed.

Cascade Bicycle Club policy director David Hiller says neither the group nor the city has studied whether the number of cyclists using Nickerson has increased. When the city put Stone Way on an equally controversial road diet, an SDOT report showed that more cyclists used the route, people drove more slowly, and declined slightly on both Stone Way and on adjacent neighborhood streets.

Perhaps the most notable fact that came out of the city's data is that pretty much everybody speeds. City budget shortfall: Solved!
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