Accident causation study on roadways with limited sight distance crest vertical curves
Date
1994
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Texas A&M University
Abstract
Stopping sight distance is an important parameter used in the design of a roadway's horizontal and vertical alignment. Many of the parameters used in the current stopping sight distance equation were developed in the 1950s and may not accurately reflect the driver and vehicle population currently on the transportation network. An accident causation study was conducted to determine if roadways with limited stopping sight distance present a safety hazard for the transportation network. Rural two-lane and multilane roadways with limited sight distance crest vertical curves were identified in three states, and accident narratives for the most recent three to five years were obtained for the selected roadways. After analyzing the accident narratives, it was determined that only 18 of the 439 accident narratives evaluated had limited stopping sight distance, during the daytime or nighttime, as a possible contributing factor. Ten of the 18 accidents with limited stopping sight distance as a contributing factor were caused by a vehicle striking another vehicle. There has been a concern that roadways with limited stopping sight distance present a significant problem for the older driver as well as large trucks. The percentage of older drivers on the selected two-lane and multilane study sites with limited stopping sight distance was similar to the percentage of older drivers in all accidents, reported by the National Safety Council. Only 30 of the accident narratives evaluated were large truck accidents. In addition, only one of the large trucks was involved in an accident with stopping sight distance as a possible contributing factor. Older drivers and large trucks did not appear to be overrepresented in accidents on roadways with limited stopping sight distance. All the accidents with limited stopping sight distance as a contributing factor occurred on vertical curves with a K value less than 125, which corresponds to 400 feet of stopping sight distance. Most of the accidents with limited stopping sight distance as a contributing factor occurred on vertical curves with a K value less than 100, which corresponds to 350-375 feet of stopping sight distance. Available sight distances less than 350-400 feet may present a safety problem.
Description
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Includes bibliographical references.
Includes bibliographical references.
Keywords
civil engineering., Major civil engineering.