AN ANALYSIS OF SAFETY AT THE TERMINALS OF CLIMBING LANES ON TWO-LANE HIGHWAYS. FINAL REPORT

This report summarizes an investigation of potentially hazardous conditions at the upper end of climbing lanes on two-lane roads in Northern and Central California. It was postulated that, at such locations, there might be sideswipe accidents involving merging vehicles or head-on collisions of a vehicle swerving across the centerline to avoid such a sideswipe with a vehicle traveling in the opposite direction. Accident records covering five years at 21 potentially hazardous locations revealed that there are very few accidents directly related to the merging maneuver. Only 11 accidents at six locations were identified. Only one of these locations had a sufficient number of accidents (5) to warrant detailed analysis. The study of this location showed that the relatively short length of the climbing lane may cause impatient drivers to attempt last-chance overtaking maneuvers, and that restricted sight distance beyond the merging area may fail to warn uphill drivers of approaching in the downhill direction. The report suggests three guidelines for the location and design of climbing lanes to be considered in addition to those found in other literature. However, the general conclusion is that the merging areas at the terminals of climbing lanes on two-lane roads do not present a hazard of major proportions.

• Corporate Authors:

  University of California, Berkeley

  Institute of Transportation Studies Library
  Berkeley, CA  United States  94720

  California Department of Transportation

  1120 N Street
  Sacramento, CA  United States  95814

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Homburger, W S
• Publication Date: 1986-5

Media Info

• Pagination: 54 p.

Subject/Index Terms

• TRT Terms: Climbing lanes; Frontal crashes; Length; Merging area; Passing; Prevention; Safety; Side crashes; Sight distance; Two lane highways
• Subject Areas: Design; Highways; Operations and Traffic Management; Planning and Forecasting; Safety and Human Factors; Security and Emergencies; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00458332
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: FHWA-CAUCBITSRR-86-3
• Contract Numbers: 13945-55B894
• Files: TRIS, USDOT, STATEDOT
• Created Date: Sep 30 1987 12:00AM