Updated February 2014
Speed-related crashes cost society an estimated $40 billion per year. It is a factor in 30 percent of all fatal car crashes, according to NHTSA. In 2005, 13,113 people died from crashes involving excessive speeding.
Speed is a factor in many crashes because of the physical forces at work. It takes longer to stop a speeding vehicle, and speed hinders the driver’s ability to detect dangerous situations. The IIHS reports that crash severity is directly related to speed. If speed increases by 50 percent, the energy released in a crash more than doubles. This increased force is what causes severe injuries and fatalities. Passenger restraint systems such as seat belts, air bags and child safety seats can be less effective at high rates of speed; this also contributes to injuries and fatalities.
Safety measures located outside the car also can be compromised. For example, at high speeds, guardrails, barriers and other devices are less effective. These devices are designed to keep cars on the roads and lessen the chances of a crash. When a vehicle is traveling at excessive speeds, these life-saving measures are much less effective.
In the early 1970s, Congress withheld federal funding from states that did not enact a maximum speed limit of 55 mph. Since then the federal government has increasingly given the power to set maximum speed limits to the states. In 1995, Congress repealed the maximum speed limit. Since then, 31 states have raised speed limits to 70 mph or higher on certain roads.
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- New! Traffic Safety Trends: State Legislative Action 2013, February 2014, by Anne Teigen and Douglas Shinkle. See Appendix G: State Maximum Posted Speed Limit Laws.
- Traffic Safety Trends: State Legislative Action 2012, February 2013, by Anne Teigen and Douglas Shinkle. See Appendix G: State Maximum Posted Speed Limit Laws.
- Traffic Safety and Public Health: State Legislative Action, 2011, No. 36, February 2012, by Anne Teigen and Douglas Shinkle.
- Traffic Safety and Public Health: State Legislative Action, 2010, No. 35, December 2010, by Melissa Savage and Anne Teigen.
- "Traffic Safety and Public Health: State Legislative Action 2009," Transportation Series No. 34, February 2010, by Melissa Savage, Anne Teigen and Nicholas Farber.