EXPERIMENTAL PLANS FOR ACCIDENT STUDIES OF HIGHWAY DESIGN ELEMENTS: ENCROACHMENT ACCIDENT STUDY

This report documents an investigation into the feasibility of using accident data to derive estimates of the rate at which errant vehicles unintentionally encroach into the roadside on level, tangent sections of two-lane rural roads. In addition, issues related to estimating the percentage of unreported accidents were also investigated. The report discusses results from the literature and an analysis of hit-utility-pole accident cases from the National Accident Sampling System (NASS). A pilot study involving 56 km (35 mi) of tangent, two-lane rural road sections in Idaho is also documented. For that pilot study, detailed roadside data were collected and accident and traffic data were obtained. Based on an analysis of that data, the resulting encroachment rate estimates were determined to be of the same order of magnitude as the encroachment rates that had been developed from previous research. It was concluded that the methodology is feasible, although it is limited by the current state of the knowledge with respect to data on the trajectories of vehicles involved in run-off-the-road and hit-fixed-object crashes. An experimental plan for future research that would produce improved estimates of roadside encroachment rates is also presented. Because the plan depends on the availability of detailed sign maintenance and roadside inventory data in electronic media, it is recommended that the plan not be implemented immediately. When and if it is implemented, the latest results from other research on trajectory data should be integrated into the plan.

• Record URL:
  https://rosap.ntl.bts.gov/view/dot/68194
• Corporate Authors:

  Bellomo-McGee, Incorporated

  8330 Boone Boulevard, Suite 700
  Vienna, VA  United States  22182

  Federal Highway Administration

  Turner-Fairbank Highway Research Center, 6300 Georgetown Pike
  McLean, VA  United States  22101
• Authors:
  • Daily, K
  • Hughes, W E
  • McGee, H W
• Publication Date: 1997-1

Language

• English

Media Info

• Media Type: Digital/other
• Features: Appendices; Figures; References; Tables;
• Pagination: 118 p.

Subject/Index Terms

• TRT Terms: Crash reports; Crashes; Future; Highway design; Ran off road crashes; Research; Right of way (Land); Rural highways; Single vehicle crashes; Studies; Trajectory; Two lane highways; Vehicle trajectories
• Uncontrolled Terms: Accident studies; Fixed objects; Future research
• Old TRIS Terms: Encroachments; Unreported accidents
• Subject Areas: Design; Highways; Research; Safety and Human Factors; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 00735912
• Record Type: Publication
• Report/Paper Numbers: FHWA-RD-96-081, Draft Final Report, 3A5A
• Contract Numbers: DTFH61-92-C-00172
• Files: NTL, TRIS, ATRI, USDOT
• Created Date: Apr 1 1997 12:00AM