The Insurance Institute for Highway Safety (IIHS) released a study demonstrating that lowering speed limits on thoroughfares and residential streets in Seattle resulted in fewer injury accidents.
This study is groundbreaking as IIHS researchers had previously looked at speed limit changes in other cities such as Boston but had never looked into the impact of lower speed limits on personal injury rates.
Earlier Study Proved Lower Speed Limits Keep Drivers In Check
Researchers found that drivers traveling on Boston roads whose speed limits had been lowered were less likely to speed. The 2018 study proved that lowering the speed limit by 5 mph on city streets can improve safety for all, not just motorists. However, researchers then did not look into the link between speed and injury accidents.
At the time, IIHS President David Harkey said that while speed-related accidents are usually thought to be a problem only for drivers traveling on highways and freeways, the Boston study showed that “speeding occurs on roads of all types.”
“Even on lower-speed roads, speeding can have deadly consequences, especially for pedestrians and bicyclists. Some cities are lowering speed limits to reduce the risks for these vulnerable road users, who are increasingly dying in crashes.”
Seattle Speed Limit Changes Improved Road Safety For Drivers, Cyclists, And Pedestrians
In the end of 2016, Seattle changed the default speed limit on arterial roads from 30 mph to 25 mph. Residential and smaller roads also saw their speed limit go from 25 mph to 20 mph. While the implementation of the speed limit change was gradual in certain areas, the new rules became widely publicized as the city launched an awareness campaign. By the end of 2019, the changes had been successfully implemented, with speed limits being lowered in eight urban centers and villages and on several arterial corridors in a variety of regions. New signals were also installed in most roads where changes were implemented.
IIHS researchers looked at the data coming from these roads following the changes and compared it to previous data. The numbers were clear: Seattle accidents were less likely to result in injuries after the speed limit changes.
When discussing the latest study, Harkey said that these findings are important because “nearly a third of crash deaths occurred on urban arterials in 2020” nationwide.
Seattle Injury Accident Rates Dropped Considerably After Changes
IIHS reported that, overall, the odds of an injury accident in downtown Seattle dropped 17 percent, while on arterial roads only, the odds of an injury crash dropped 20 percent in downtown Seattle and 11 percent outside the central city area.
If anything, these numbers help us understand how speed limits help to change drivers’ speeding behavior, which can contribute to a safer driving experience.
IIHS: Other Cities Should Take Similar Approaches
When discussing the study’s findings, IIHS Senior Research Transportation Engineer Wen Hu said that other communities could benefit from similar changes.
“To reduce injuries even further, communities should combine lower speed limits with engineering solutions, public education about the importance of reduced speeds, and high-visibility enforcement,” the lead author of the study added.
If you would like to read more about the study, its methodology, and its results, follow this link.
