Background: Nationwide reduction of speed limits to 65 miles per hour (mph) has the potential to save 2,985 lives every year. We undertook the current study to measure potential cost savings of implementing this injury prevention strategy.
Methods: Using the National Highway Traffic Safety Administration's CRASHCOST software, we determined costs of motor vehicle injuries in the 29 states with speed limits exceeding 65 mph in 2003. CRASHCOST estimates lifetime economic costs associated with motor vehicle crashes. Next, we calculated the expected number of crashes, and associated costs, if speed limits were reduced to 65 mph nationwide. Estimated crash rates after reduction were derived by comparing states with speed limits up to 65 mph versus >65 mph, adjusted for vehicle miles traveled, safety belt use, and other confounders. Potential savings were defined as the difference between the two costs.
Results: Estimated potential savings with restriction of speed limits to 65 mph is $13 billion annually, including a $2 billion reduction in trauma care costs. These savings reflect approximately 6% of the total economic impact of motor vehicle crashes ($231 billion in 2000). To put these costs into perspective, National Highway Traffic Safety Administration estimates $50 billion in annual savings with safety belt use, $1.94 billion with airbags, and $670 million with motorcycle helmets.
Conclusions: Nationwide reduction of speed limits to 65 mph has the potential to save $13 billion nationally every year. Hence, legislative action on speed limits will not only reduce motor vehicle injuries and deaths, but will also provide significant cost savings.