End date: 06/01/08
About the research
The conversion of two-lane roadways to four-lane, divided expressways has become a common solution to the need for high-speed, higher capacity travel between rural and suburban communities. As traffic volumes increase on these facilities there are seemingly inevitable increases in intersection crashes. A frequently proposed solution to intersection crashes is the installation of traffic signals, with results that can at best be described as mixed. In some cases there have been reductions in crash risk following signalization while in others there has been no change or even an increase. The public perception seems to be that signals are the universal fix, while transportation safety specialists at present cannot state with assurance that installing signals at a particular intersection will be successful at reducing the frequency of problem crashes.
In an effort to provide some indicators for the safe signalization of high-speed intersections, this study focuses on an analysis of a variety of intersection characteristics and how they relate to crash risk at these intersections. This project expands upon work by Souleyrette and Knox (2005) that evaluated the safety of signalized intersections on high-speed expressways.
Report: http://www.intrans.iastate.edu/reports/signal_intersections.pdf (294 kb pdf) June 2008
Sponsor(s): Iowa Department of Transportation