New Headlights Sharpen Night Vision
Seeing ahead of the curve
by Cathy Nikkel

As summer fades into fall, the hours of daylight shrink, fog and rain increase, and deer become more active at night. These factors all add up to lowered visibility and heightened hazards. Studies show that visual perception, with which we absorb 90 percent of all relevant traffic information, is reduced to as little as four percent during foggy, rainy nights. Reduced vision increases reaction timeóand that can have fatal consequences. Between the hours of 9 p.m. and 6 a.m., pedestrian deaths reach a statistical peak and more than half of all fatal crashes occur involving teenagers. Drivers rely on headlights during these dangerous periods for a clear view of the road and to illuminate hazards ahead.
The good news is that standard headlights are undergoing a technology revolution as automakers turn engineering and computer resources on improving a driver's nighttime view of the road. New adaptive headlights like those shown on the Volvo Safety Concept car a few years ago are able to move with the steering direction of the vehicle. Instead of pointing straight ahead, these headlights adapt to the path of the vehicle and continue to illuminate the road directly ahead even through curves. Different versions of these headlights are showing up on high-end models including Volvo, BMW and Infiniti.
Ford is demonstrating a more advanced headlight system on its Smart Safe Research Vehicle (S2RV), a modified Ford Explorer. Ford's adaptive headlamp technology uses digitally controlled beams to dynamically adjust the light pattern according to driving conditions, safety requirements, or driver preferences. It uses feedback from vehicle onboard computer systems, such as steering wheel angle and vehicle speed, to optimize illumination for any given situation. The headlamp unit is controlled electronically to create beam patterns that vary in angular extent or shape, intensity, time, or any combination of those. For example, at an intersection, the headlights project a broader beam but narrow down again when the vehicle has moved through the intersection and continues down the road where a narrower but more distant area needs to be illuminated. When turning corners, the headlights automatically reduce glare for oncoming traffic.
Ford's adaptive headlamp system has leapfrogged other systems that mechanically turn the headlights to follow the vehicle's path. Since these systems rely on a mechanical movement, they can take a little longer to respond. Ford is utilizing the technology in projection optics in its concept headlamp. The automaker's digital light processing technology, based on that used in military and aircraft as well as business and cinema projectors, allows a programmable system that can actually change the illumination precisely for specific circumstances, rather than just rotating on a fixed pattern.
Ultraviolet Light
Ford is also participating in a research project with the Virginia Tech Institute for Transportation Research funded by the Federal Highway Administration to improve night visibility with ultraviolet or black light bulbs in the headlights. Research in Sweden shows that using fluorescent (glow in the dark) pavement markings and ultraviolet headlights in conjunction with low beam headlights can double visibility during wet-night road conditions, says Gary Allen director of the Virginia Transportation Research Council. Preliminary tests show that ultraviolet headlights allow drivers to see up to 30 percent farther at night and also increase visibility of pedestrians.
Ultraviolet or "black lights" reflect fluorescent materials. Because the phosphates left in our clothes after laundering are fluorescent, the ultraviolet headlights will make pedestrians glow like disco dancers. Special road markings, provided by 3M, Day-Glo Color Corporation and Carsonite International, that fluoresce are also being tested on the Virginia Tech transportation center's "Smart Road." This test road can create snow and rain and fog conditions. The headlights and pavement markings will also be tested on real roads in Montgomery County, MD and Afton Mountain near Charlottesville, VA. Volunteers' cars will be retrofitted with Ford's prototype headlights to test real traffic conditions. Researchers will look at whether the materials are stable and environmentally sound, how long they will last, and where and under what conditions fluorescent materials are most useful.
If a UV system proves beneficial, researchers in the Virginia Tech center will help develop policies and procedures to deploy safer equipment and road markings, according to Aaron Schroeder, a senior research associate with the center who will facilitate the deployment phase. "We will work with automakers, public safety interest groups, state departments of transportation, and federal agencies to come up with programs to deploy the technology in cars and on roadways," Schroeder says.