PSU Study Evaluates Impact of Speed Limit Reductions in Portland, OR on Driver Speeds

In 2015 the City of Portland adopted a Vision Zero plan. Crash data revealed that speed was a contributing factor in 47% of fatal crashes in Portland. In 2018, the City Council reduced the speed limit on all residential streets to 20 mph. Funded by the Portland Bureau of Transportation and conducted at PSU by Monsere, Kothuri and Jason Anderson, this study looked at the before and after the speed limit changes at 58 locations and found that the change likely reduced driving speeds by small but significant amounts. The speed reduction in the percentage of vehicles faster than 30 mph and 35 mph on residential streets are larger in magnitude than other observed impacts.

https://trec.pdx.edu/news/effect-residential-street-speed-limit-reduction-25-20-mihr-driving-speeds-portland-oregon