ACCIDENTS BEFORE AND AFTER THE 65 MPH SPEED LIMIT IN CALIFORNIA. FINAL REPORT

This report examines the impact of the 65 mph speed limit on traffic accident rates on rural interstate highways posted at 65 mph, rural interstate highways posted at 55 mph, and the "look-alike" non-interstate posted at 65 mph. Two statistical methods under the general heading of analysis of variance (ANOVA) were used to determine whether there were systematic differences between the observed changes in the accident rates on the above three categories of highways. The results show that rural interstate segments where speed limits were maintained at 55 mph generally had a significant decrease in accident rates from the levels that were observed prior to the year the speed limit was increased to 65 mph. By contrast, the rural interstate posted at 65 mph, and the "look-alike" non-interstate roads generally had a significant increase in their accident rates.

• Corporate Authors:

  California Department of Transportation

  Division of Traffic Operations, 1120 N Street
  Sacramento, CA  United States  95814
• Authors:
  • Khorashadi, A
• Publication Date: 1992-9

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 23 p.

Subject/Index Terms

• TRT Terms: 65 mph speed limit; Analysis of variance; Before and after studies; Crash rates; Interstate highways; Rural highways; State highways
• Geographic Terms: California
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; Safety and Human Factors; I73: Traffic Control; I81: Accident Statistics;

Filing Info

• Accession Number: 00625381
• Record Type: Publication
• Report/Paper Numbers: CA-TO-92-4, Rept 51-358-908074
• Files: TRIS, STATEDOT
• Created Date: Nov 23 1993 12:00AM