Safety and traffic flow issues are related to drivers selecting inappropriate speeds when driving. For example, at some curved interchange exit ramps, drivers may go too fast, increasing the risk of rollover crashes, especially for heavy trucks. At other locations, perceived 'bottlenecks' in roadway geometry may cause some drivers to slow down more than is appropriate, resulting in variations among vehicle speeds, and increasing the likelihood of traffic congestion, delays and rear-end crashes.

The project team from the Lighting Research Center at Rensselaer Polytechnic Institute, in response to a New York State Department of Transportation (NYSDOT) request for proposals (RFP), proposes to investigate lighting approaches for two roadway applications with the objective of identifying configurations of lighting that can encourage slower speeds at curved ramps, and can encourage drivers to maintain their speeds in locations prone to traffic congestion.

This investigation will consist of three primary phases. The first phase will extend our previous work using laboratory and simulation studies to measure drivers' perceptions to various lighting configurations. The second phase will involve design, development, installation and evaluation of a lighting system for encouraging speed reductions at an actual curved ramp location in New York State's capital region. The third phase will employ a similar series of tasks with the objective of encouraging drivers to maintain their speed at an actual location in the capital region where traffic congestion has been problematic. The latter phases will be informed by a review and analysis of the appropriate lighting technologies for providing the necessary visual information to drivers, focusing on, but not entirely limited to, solid state lighting using light emitting diode (LED) sources. Based on the results of the initial studies and of the evaluations of the lighting installations at each location, the project team will develop preliminary specification guidance to NYSDOT about where, when and how similar approaches could be used at other locations across New York State.