Researchers develop new method to light roundabouts

Roundabouts, also known as traffic circles,  generally increase traffic throughput while reducing the severity of automobile accidents. However, as relatively new traffic features, modern roundabouts are sometimes described as confusing for drivers.

One difference between roundabouts and conventional cross-type intersections is the location of pedestrian crosswalks. Drivers may be less familiar with the location of crosswalks when driving through a roundabout.

The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute has developed a concept for roadway illumination called "Ecoluminance", which incorporates roadside vegetation with low-level pedestrian and landscape lighting, retroreflective markers, and light-emitting diode (LED) road and walkway illumination.

In a study sponsored jointly by the New York State Energy Research and Development Authority (NYSERDA) and by the New York State Department of Transportation (NYSDOT), the LRC designed, installed and evaluated new lighting approaches in real-world conditions. Senior research scientist John Bullough and LRC director Mark Rea were the principal investigators for the study.

''Ecoluminance uses a combination of lighting and vegetation to provide visual delineation, illumination for important safety hazards and concerns, and cues about road geometry,'' said Bullough.

The ecoluminance concept was implemented at a roundabout in the Town of Bethlehem in Albany County, New York, with cooperation from the town board and the public works, highway, planning, and police departments.