Seattle Stats Show Rechannelization Works Well
The Nickerson Street rechannelization has reduced speeding and collisions without affecting traffic volumes. Such projects are among nine proven countermeasures recommended by FHWA in January.
Seattle officials offered traffic safety data on March 1 showing how the Nickerson Street rechannelization project completed in August 2010 has cut speeding and reduced collisions while maintaining traffic volumes. The project by the Seattle Department of Transportation was intended to increase safety -– especially for pedestrians -– as well as drivers' compliance with speed limits.
Some crosswalks were removed and two were added; a sharp curve was smoothed and the travel lane was widened by 1 foot to help freight movement. SDOT monitored traffic patterns before and afterward. The data show:
- Collisions declined by 23 percent in a one-year period compared to the previous five-year average
- Motorists exceeding the speed limit have declined by more than 60 percent
- Top-end speeders (people traveling 10 or more miles above the speed limit) declined by 90 percent
- The 85th percentile speed dropped from 40 mph and 44 mph westbound and eastbound to 33 mph and 33 westbound and eastbound, which represents 18 percent and 24 percent reductions in speed
- Traffic volumes are roughly the same, with no evidence of traffic diversion
"As our recent Road Safety Summit highlighted, all of us want to reduce collisions on city streets while working toward zero fatalities and serious injuries," Mayor Mike McGinn said. Chief Gregory Dean of the Seattle Fire Department said reducing collisions helps his emergency crews respond more quickly to accidents.
The project was the 28th road rechannelization completed in Seattle since 1972; there are 36 citywide. A Federal Highway Administration memorandum issued earlier this year recommended nine research-proven countermeasures that have the greatest effect on improving safety, and road diets -– also known as road rechannelizations -- were included.