Vari-Lite Joins Research Project to Make Driving Safer
Published Wednesday, April 28, 2004

A VARI*LITE® VL1000™AS luminaire plays a critical role in a research study the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute (RPI) hopes will make nighttime driving safer for everyone. The automated luminaire will be used to simulate the headlamp of an oncoming vehicle.

Vari-Lite loaned the VL1000 fixture for the three-month study, which will investigate how the headlamps affect driver glare recovery time after passing the oncoming vehicle. The objective of the project, according to LRC research lab technician Martin Overington, is to determine the photometric performance of different headlamp types. When completed, a written report will be submitted to the National Highway Traffic Safety Administration (NHTSA).

"When the LRC contacted Vari-Lite and explained the project, we jumped at the chance to participate," said Vari-Lite spokesman Jeff Morrison.

When two vehicles approach each other, the illuminance on the driver's eyes increases from a small to high intensity, then cuts quickly. Using the automated four-blade shutter system on the VL1000 luminaire, researchers can simulate different sized and shaped headlights then compare their effects. They can also study the impact that the new high-intensity headlamps have on drivers' vision.

From this research, engineers can develop headlamps in sizes, shapes and beam patterns to minimize the intensity and glare that causes momentary blindness to an approaching driver and improve highway safety.

"We needed a fixture that can generate variable intensity and orientation to simulate an oncoming vehicle," said John Van Derlofske, head of transportation lighting research at RPI. "We want to create the profile exactly as it would be if two cars were passing each other on the roadway. Once we have that profile, we will test and see how long it take the driver's vision to return to its previous state."

Researcher will use the shutters to create the profile and then program the aperture of the fixture to simulate an approaching vehicle. The beam will start out dim, as if the vehicle is in the distance, and gradually increase in illuminance at the eye as if the vehicles were coming toward one another. Different test will be run to simulate different vehicle speeds.

If you imagine two cars coming at each other, if they are 100 feet away, the headlamps will project a certain amount of light into the opposite driver's eyes. As the vehicles get closer and closer, the amount of light will change based on the headlamp beam pattern and the speed of the vehicle.

"What we're really interested in is changing the amount of light as a function of time to fit this precise profile," Van Derlofske explained. "The reason we can't simply regulate it by voltage is because that alters the color of the light."

If a low voltage is used, it will produce a yellowish colored light. A high voltage produces a more blueish tone. Researchers want the color to remain constant, which is where the shutters and color-regulating system of the VL1000 luminaire comes into play. The spectral power distribution of the VL1000 fixture will not shift (change color) with a change of the intensity.

"Technology is changing," Van Derlofske said. "We have new kinds of lights - high intensity discharge lights, new lamp coatings, better optical design. With these new innovations being integrated into automobile headlamps, the NHTSA wants to take a look at the headlamp glare situation. The big idea is to try and make it safer."

In commissioning the study, the NHTSA wants to determine if there is a problem, and if there is a problem, what is its magnitude. The research should provide the NHTSA with enough data that the NHTSA can determine if the issue is something that should be regulated or looked at by automobile manufacturers. Ultimately, the goal is to find a way to minimize headlamp intensity, glare or beam angle into the eyes to make nighttime driving safer.

Morrison added, "This is just another example of how different industries are benefiting from automated lighting technologies. Twenty-five years ago VARI*LITE developed the first automated fixtures for the sole purpose of lighting rock and roll shows. Now they're being used to save lives."

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