Small speed increases can also have huge effects on crash outcomes for drivers and passengers. Crash tests by the AAA Foundation for Traffic Safety, IIHS, and Humanetics found that as crash speeds increased from 40 mph to 50 and 56 mph, the test vehicle had more structural damage and greater forces were registered on the test dummy’s entire body. The researchers concluded that even relatively small increases in speeds of 5 or 10 mph increase a driver’s injury and fatality risk.
"Speeding drivers may arrive at their destinations a few minutes quicker, but is the tradeoff of getting injured or losing one's life worth it if a crash occurs?" says David Yang, executive director of the AAA Foundation for Traffic Safety.
To make matters worse, speeding historically has led to higher speed limits. In many states across the West, including Arizona and California, speed limits are set using the 85th percentile method, a federal standard that many cities and states are now moving away from, including Oregon. Under this principle, engineers survey a stretch of road, typically every 10 years, to see how fast people are driving. Officials then set the speed limit based on how fast 85 percent of drivers were going. This has led to speed limits creeping up across the country, and rather than driving the new speed limit, people still continue to exceed it. A 2019 IIHS study found that rising speed limits across the U.S. have caused an additional 37,000 people to be killed between 1993 and 2017.