Highway Safety:

Factors Contributing to Traffic Crashes and NHTSA's Efforts to Address Them

GAO-03-730T: Published: May 22, 2003. Publicly Released: May 22, 2003.

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Peter F. Guerrero
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From 1975 through 2002, annual traffic fatalities decreased from 44,525 to 42,850, while the rate of fatalities per 100 million vehicle miles traveled decreased from 3.35 to 1.51. However, decreases in fatalities have leveled off since the early 1990s. Since 1999, the number of alcohol-related fatalities has risen. In 1998, the Transportation Equity Act for the 21st Century funded a series of highway safety programs. These programs, administered by the National Highway Traffic Safety Administration (NHTSA), increased funding to the states for activities designed to encourage, among other things, the use of seat belts and to prevent drinking and driving. The states establish highway safety goals and initiate projects to help reach those goals. NHTSA provides advice, training, and technical assistance to states and can use management reviews and improvement plans as tools to help monitor and strengthen the states' performance. This testimony is based on two recent GAO reports that discuss the causes of motor vehicle crashes and related research, provide highway saftey trend data and information on federal highway safety funds and the states' uses of those funds, and review NHTSA's oversight of state highway safety programs.

Most motor vehicle crashes have multiple causes. Experts and studies have identified three categories of factors that contribute to crashes--human, roadway environment, and vehicle factors. Human factors involve the driver's actions (speeding and violating traffic laws) or condition (effects of alcohol or drugs, inattention, decision errors, and age). Roadway environment factors include the design of the roadway, roadside hazards, and roadway conditions. Vehicle factors include any failures in the vehicle or its design. Human factors are generally seen as contributing most often to crashes, followed by roadway environment and vehicle factors. To improve highway safety through programs that primarily address the human factors that contribute to traffic crashes and fatalities, about $2 billion was provided to states over the last 5 years for highway safety programs under the act. About $729 million was provided under Section 402, the core highway safety program, and about $936 million was provided through seven incentive programs, mainly for efforts to influence driver behavior. Another $361 million was transferred from state highway construction to state highway safety programs under provisions that penalized states for not complying with federal requirements for passing laws to reduce drinking and driving. GAO found that NHTSA's oversight of state highway programs could be improved. NHTSA regional offices have made inconsistent use of management reviews and improvement plans because NHTSA's guidance does not specify when to use them. As a result, some states do not have improvement plans, even though their alcohol-related fatality rates have increased or their seat-belt usage rates have declined. Without improvement plans NHTSA may not fully realize its goals in working with the states to improve highway safety. GAO recommended in an April 2003 report that NHTSA provide guidance to its regional offices on when it is appropriate to use these oversight tools. NHTSA is taking steps to improve this guidance.

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