Lower speed limits introduced in Seattle has meant crashes were less likely to cause injuries, a new study by the Insurance Institute for Highway Safety (IIHS) has shown.
In November 2016, Seattle lowered the default speed limits from 30 mph to 25 mph on its arterial roads and from 25 mph to 20 mph on smaller, mostly residential streets.
According to research by the IIHS, in downtown Seattle the move meant the likelihood that a crash would involve an injury was slashed by a fifth on arterial roads.
Outside of the city center, where the new limits were less consistently implemented and publicized, there were smaller injury reductions.
An earlier IIHS study showed that lowering speed limits in Boston resulted in less speeding, but it didn’t investigate the impact on crash or injury rates. The new study of Seattle’s program is one of the first to examine the effect of lower limits on injury rates in a large, populous US city.
“Everybody thinks of highways when we talk about speed limits, but reducing speeds on city thoroughfares and residential streets is just as important,” said IIHS President David Harkey.
“Nationwide, nearly a third of crash deaths occurred on urban arterials in 2020.”
