Changes to Nickerson St in 2010 have resulted in a 23 percent drop in collisions, the city reported during a press conference today.
Last year, Publicola reported that traffic volumes on Nickerson remained consistent, as the city had predicted. Average speeds dropped from over 40 mph to 34-37 mph, which is still higher than the speed limit.
We’ll have more details soon (UPDATE: See below), but this appears to be yet another example that such road design improvements (AKA “road diets”) work dependably at increasing safety without negatively impacting traffic congestion.
The Nickerson redesign was fairly controversial, with opponents claiming there would be massive traffic jams and accusing the mayor of being too pro-bike. While the added bike lanes on Nickerson certainly help people access businesses and homes along the Nickerson corridor by bike, the project was hardly about just bikes. The Ship Canal Trail provides a better alternative for people passing through the area on bike (especially now that it has been extended to Fisherman’s Terminal). Rather, the Nickerson project was about road safety for everyone, as it appears to have done.
UPDATE: You can see the full study report below. The study found that the number of people driving more than 10 mph above the speed limit dropped by a staggering 92-96 percent.
Here’s a before-and-after shot. Notice how much more inviting the after image is for people who need to cross the street to access that bus stop.
The study also found that daily traffic volumes on Nickerson remained unchanged. The number of freight trucks of all sizes even increased slightly. The AM peak traffic volumes did drop significantly, but this was not due to people taking alternative routes. 15th Ave W actually saw an even larger decrease in AM traffic, so that decrease may be a sign of a larger traffic trend in the area and not related to the road changes.
SDOT’s official conclusion:
The Nickerson rechannelization enabled SDOT to install two new marked crosswalks. The rechannelization improved all marked and unmarked crosswalks on the corridor by reducing the multiple lane threat where one lane of traffic stops but the second lane does not. The project improved traffic safety overall by dramatically reducing the percent of drivers traveling more than 10 miles per hour over the speed limit. The percent of drivers traveling over the speed limit has been reduced by more than 60% and the percent of top-end speeders has been reduced by 90%. Traffic volume remains roughly the same as it was before the rechannelization. There is no evidence that the rechannelization has resulted in traffic diversions.
UPDATE: Here’s the mayor’s statement on the changes.