Safety Evaluation of Cross-Sectional Elements of Freeway Managed Lanes

Abstract

This paper investigated the safety implications of managed-lane cross-sectional elements. The objective of the Federal Highway Administration project was to investigate the relationship between crashes and buffer-separated managed lane dimensions. The results from several previous research studies have demonstrated that reductions in freeway lane width or shoulder width are associated with more crashes. This research found that a narrower managed-lane envelope width (i.e., left shoulder, managed-lane, and buffer width combined) is also associated with more freeway crashes for crashes of all severity levels including fatal and injury. Wider envelopes are associated a reduction in total freeway crashes, of all severities, of 2.8% in Texas, and 2.0% in California, for each additional foot of envelope width. In California, wider envelopes are associated with a reduction of 4.4% in managed-lane-related crashes resulting in fatalities and injuries at all severity levels, for each additional foot of envelope width. The analysis was conducted on nonweaving managed-lane segments that included a single managed-lane separated from the general-purpose lanes with a flush buffer area. The dataset included crashes on 128.0 miles of freeway in California (all 128.0 miles with flush buffers) and 60.4 miles of freeway in Texas (41.7 miles with pylon buffers and 18.7 miles with flush buffers). The California sites included freeways with three or four general-purpose lanes, and the Texas freeways had three to five general-purpose lanes.

Influence of Multiple Freeway Design Features on Freight Traffic Safety

“…ere have been a number of studies which tried to assess the safety of freeway [3][4][5][6][7] by simple comparison methods and traffic simulations. ere are also studies that addressed freight safety by investigating the risk factors that contribute to severity of truck-involved crashes [8][9][10][11][12][13][14][15][16][17].…”

Short-Term Safety Performance Functions for Freeways Including High Occupancy Vehicle Lanes

“…These kinds of models cannot capture short-term traffic turbulence. As for the HOV scenarios, some studies adopted developing crash prediction models focusing on HOV lanes ( 1, 26–29 ). Most of them focused on investigating the relationship between the geometric design of HOV lanes and the related crash frequency.…”