SAFETY ASPECTS OF THE NATIONAL 55 MPH SPEED LIMIT

This article summarizes recent research, performed by the Pennsylvania State University, which evaluated the effect of the national 55 mph (89 km/h) speed limit on highway safety. It also contains analysis by the authors which shows that the reduction in speeds, brought about in part by the new speed limit, prevented over 4,700 fatalities and 81,000 injuries in 1974. In the university research, fatality rates and injury rates occurring after the speed limit reduction were compared to projected rates based on pre-speed limit data. A comparison was made of nationwide data for various highway systems and for a selected representative sample of States. The study shows that, under the national 55 mph (89 km/h) speed limit, fatality rates decreased most on highways where speed limits changed most, particularly the Interstate Highway System. However, injury rates were not generally below expected rates based on past trends, except that the Interstate Highway System did show a large decrease. Additional factors studied were pedestrian fatalities, age of driver in fatal accidents, time of fatal accidents, and type of vehicle involved. The authors' additional effort involved regression and correlation analyses of the effects of various speed measures on corresponding fatality and injury rates. Six years of data were employed in this analysis. /Author/

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    Federal Highway Administration

    Office of Research and Development, 1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Kemper, W J
    • Byington, S R
  • Publication Date: 1977-9

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Filing Info

  • Accession Number: 00173504
  • Record Type: Publication
  • Report/Paper Numbers: HS-021 304
  • Files: HSL, TRIS, USDOT
  • Created Date: Apr 12 1978 12:00AM