By Frank Gross, Ram Jagannathan, Warren Hughes
Vienna, VA (August 13, 2009)-Trees are one of the roadway design elements that can reduce vehicle speeds by 3 to 15 mph according to a study in the Journal of the Transportation Research Board.
The Federal Highway Administration’s (FHWA) Office of Safety has identified intersections as one of its safety focus areas. As part of FHWA’s efforts to reduce intersection crashes and related injuries and fatalities, two low-cost concepts have been identified:
(a) Lane narrowing on major road intersection approaches.
The lane-narrowing concept was shown to significantly reduce speeds and crashes on the major road approaches. The average speed reductions for all vehicles (3.5 mph) and for trucks only (4.4 mph) were statistically significant at the 95% confidence level. Total, fatal and injury-only, and angle crashes were reduced after deployment, but only the reduction in fatal and injury-only crashes was significant at the 95% confidence level.
(b) Installing channelizing islands and supplemental stop signs on minor road intersection approaches.
The minor road channelizing concept is shown to improve driver compliance with traffic control and to reduce speeds and crashes on minor approaches. The average speed reductions on minor approaches (nearly 10 mph) were statistically significant at the 95% confidence level. The crash rate for total, fatal and injury-only, angle, and rear-end crashes decreased after deployment.
With the cooperation of several transportation agencies, these strategies were deployed at a limited number of sites in the United States; specifically, the concepts were deployed at two-lane, two-way, stop-controlled intersections. Positive operational and safety effects were observed with the installation of the two strategies.
Issue: Volume 2092 / 2009
Category: IVA Planning Highway Operations, Capacity, and Traffic Control
Two Low-Cost Safety Concepts for Two-Way, Stop-Controlled Intersections in Rural Areas