The purpose of this research was to investigate the effect of clear zone widths on accidents and to determine the "break-even" traffic volumes and clear zone widths where accident savings equalled roadside improvement costs. Although sufficient data was not available to determine the statistically significant combined effects of clear zone widths and traffic volumes on accident frequency, some very logical trends were observed which provided the basis for accident prediction models and cost-safety-effective analyses. The cost of clearing the roadside of fixed objects (trees, culvert headwalls and entrances) was generally greater than the present worth of the cost of all collisions involving these objects for most highway segments. For those segments whose accident costs were higher, remedial action should be considered. Generally, these segments have higher ADTs than other segments. In contrast, for all segments examined the cost of flattening the side slopes and removing all fixed objects exceeded the present worth of the savings from the predicted reduction in run-off-road accidents.

  • Corporate Authors:

    Illinois Transportation Research Consortium

    Chicago, IL  United States 

    Illinois Department of Transportation

    Bureau of Design and Environment, 2300 South Dirksen Parkway
    Springfield, IL  United States  62764

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Boyce, D E
    • Hochmuth, J J
    • Meneguzzer, C
    • Mortimer, R G
  • Publication Date: 1989-10

Media Info

  • Pagination: 131 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00496565
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA/IL/RC-003
  • Contract Numbers: IHR-010
  • Files: TRIS, USDOT
  • Created Date: Aug 31 1990 12:00AM