A table is presented, of 634 studied classified by 17 improvement codes, which evaluates the effectiveness of the various types of safety improvements. A summary is also tabulated of the construction cost data contained in the before-and-after evaluation studies. Teh average cost of a safety improvement project was $109.968. Tables also show that for 15 types of improvements, the percentage reduction in total accidents varied from 4.8 percent for code 60 (installation or up-grading of traffic signs) projects to 61.5 percent for code 31 (replacement of bridge or other major structure) projects, with 10 of the 15 reductions statistically significant at the 5 percent level. Comparision of the types of improvements on the basis of equivalent uniform annual construction costs per accident reduced, reveals different types of improvements as more effective. Thus, the 4 most cost-effective types of improvement are shown to be codes 64 (installation of striping and/or delineators), 99A (installation of flashing beacons), 60 (installation or up0grading of traffic signs), and 11 (traffic signals installed or improved). Tables are also presented which show the accident rate per 1,000,000 vehicles for the various types of improvements, and the percentage distribution of the number of accidents by accident severity before and after safety improvements. A summary is also presented of safety improvement project data from state highway Departments which could enlarge the base for evaluating the accident-reducing effectiveness of safety improvement projects. The test for statistical significance is discussed in an appendix.

  • Corporate Authors:

    Federal Highway Administration

    Office of Safety and Traffic Operations, 1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Dale, C W
  • Publication Date: 1973-5

Media Info

  • Features: Appendices; Tables;
  • Pagination: 13 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00135030
  • Record Type: Publication
  • Files: TRIS, USDOT
  • Created Date: Oct 6 1976 12:00AM