Advancing the effective use of light for society and the environment.

Friday, October 3, 2003

Shedding light on emergency vehicles

With high-profile traffic accidents involving collisions with police vehicles alongside the highway, LRC researchers have released a brief statement regarding emergency lighting for police cars and other emergency vehicles. The LRC seeks to encourage discussion based on facts rather than assumptions.

LRC scientists are currently working on a number of transportation/vehicle-related lighting projects, including evaluation of HID headlamps for the National Highway Traffic Safety Administration.

Blue Lights and Police Vehicle Safety
On August 25, 2003, New York State Attorney General Eliot Spitzer issued a legal opinion that New York state vehicles cannot legally use blue lights because this color is reserved for volunteer firefighters. Claims for the superiority of blue lights over those of other colors have been made, and in response, state Sen. Nicholas Spano of Westchester County has proposed a bill to permit the use of blue lights on police vehicles. But are blue lights really safer?
Color: The Wrong Tool for the Job
Reports of accidents involving drivers crashing into police vehicles as they are parked along the side of the road are all too common. The idea that blue lights might make a police vehicle more visible at first makes sense. There usually aren't many blue lights found along the roadway, and their uniqueness might be an extra benefit to a driver approaching a stopped police vehicle.

Research by the Lighting Research Center at Rensselaer Polytechnic Institute has shown that while the color of a signal light can make a small difference in visibility when the signal is very difficult to see, the flashing and strobe lights found on emergency and hazard vehicles are designed to be very visible and stand out from their background, no matter what color they are. At these levels, color no longer makes an important difference. It simply is a tool to help us distinguish among different kinds of emergency or hazard vehicles.
Flashing Lights: Are We Overdoing It?
Plowing snow is a common activity in the Northeast, and snowplows are often equipped with flashing or strobe lights to enhance visibility. In a study of rear lighting on snowplow trucks, the Lighting Research Center found that people had much greater difficulty judging how fast they were approaching a snowplow from behind when flashing lights were used than when steady-burning lights were used.

The same principles apply to police vehicles and to any other emergency or hazard vehicle. Flashing lights are excellent "attention-grabbers," but they can sometimes overpower brake and tail lights on vehicles. When flashing and strobe lights are used, steady lights bright enough to be seen should also be used. These will help drivers make better judgments when they approach a stopped police vehicle, and can help reduce an important threat to our law enforcement officials.


About the LRC

The Lighting Research Center (LRC) is part of Rensselaer Polytechnic Institute and is the leading university-based research center devoted to lighting. Founded in 1988, the Lighting Research Center has built an international reputation as a trusted and reliable source for objective information about lighting technologies, applications, and products. Its mission is to advance the effective use of light and create a positive legacy of change for society and the environment



2003 Rensselaer Polytechnic Institute, Troy, NY 12180 USA.

Rennselear Polytechnic Institute