Researchers propose safer high beams all the time

[February 03, 2009]  TROY, N.Y. (AP) -- Researchers may have refined a way to help with the old problem of high-beam headlights temporarily blinding oncoming drivers.

After studying roadway glare for two years, researchers at Rensselaer Polytechnic Institute's Lighting Research Center said their rough prototype blocks a measured slice of an auto's light beam projecting into the other lane.

In their lab in Troy, center director Mark Rea stood squinting in front of a blazing headlamp while colleague John Bullough slid a small metal finger behind the lens to demonstrate. Rea was able to open his eyes wide even as the light shone all around him.

He laughingly called it "guilt-free visibility."

Their work is funded by $890,000 from the National Highway Traffic Safety Administration. Glare is believed to be a major reason the traffic fatality rate is about three times higher at night.

If anything, the problem has gotten worse in the past decade with high-riding SUVs and pickup trucks. Also, some newer cars are equipped with blue-tinged "high-intensity discharge" (HID) lights, which bother some drivers.

Clicking off the brights reduces glare, but it also leaves drivers with a less expansive view of the road. And besides, studies have shown most people don't even use their high beams.

Rea said that if you're driving faster than 30 to 40 mph with low beams, you're "overdriving your headlights." In other words, a lot of drivers are not seeing enough of what is coming at them.

"Ultimately, we have to come up with something better than low beams," said Bullough, who runs the center's Transportation Lighting Program.

Bullough and Rea propose driving with high beams on all the time, but with the system that can sense oncoming traffic and self dim in the appropriate direction. It can be done with a simple shadow-making shim, as in the Troy lab. On newer LED headlights, selected diodes can be dimmed at the appropriate time.

Such dimming systems could also be used to protect drivers ahead from rearview mirror glare.

The concept is not entirely new. Michigan-based Gentex Corporation, for example, makes a traffic-sensing system called SmartBeam that dims high beams when cars approach. Company officials say it's available on about 20 models worldwide.

Michael Flannagan of the University of Michigan Transportation Research Institute said the concept of just shading a portion of high beams has been around for a while, though it's only become technically feasible in recent years.

Rea and Bullough suggest 3 to 4 degrees of the high beam should be blocked for roadway safety. The researchers are offering the traffic safety agency performance specifications for manufacturers that choose to make such a headlight, whether it's halogen, HID or LED. They'll also present their idea soon to headlight manufacturers.

"In concept, people have kicked it around for decades," said Flannagan. "It's the right thing to do."

But it would come at a cost. Consider that replacement LED headlights can cost more than $200, and that's without sensors. Rea said the cost would be rolled into the price of a new car. He said the benefits of safer roads will outweigh potential costs.

"I think in three years you're going to see this on cars," he said.

___

On the Net:

RPI Lighting Research Center: http://www.lrc.rpi.edu/

National Highway Traffic Safety Administration:
http://www.nhtsa.dot.gov/

[Associated Press; By MICHAEL HILL]

Copyright 2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.