If driving at night has become more difficult, don’t necessarily blame your headlights. Once you move out of your 20s, there’s a good chance that the problem has nothing to do with your car’s equipment and everything to do with your age.
Baby Boomers are getting old, and one sign of that is a loss of visual acuity. “When you’re 45, you need 50 percent more light to see as well as you did when you were 25,” said Jeff Erion, lighting manager for Visteon Automotive Systems in Dearborn, Mich.
Facing the largest group of geezers in history, the automobile industry has an economic incentive to make things brighter. The relaxation of federal regulations and the advent of powerful computer software have enabled the industry to create new headlight designs in record time.
In any headlight, the light needs to be properly dispersed. A bulb generates light back toward an aluminum-coated reflector, which then reflects it toward the front of the headlight, which may have a plastic or glass lens. In a traditional parabolic headlight, up to 200 facets on the lens direct the light onto the road, which ensures that the beam is wide enough, evenly spread and aimed in the correct direction to illuminate road signs, while not shining in oncoming drivers’ faces.
There are other designs as well: jeweled headlights do not use lenses, while projection-beam headlights do. The newest trend is the jeweled, clear, headlight. Stare into a jeweled headlight (unlighted, if you’re smart) and you can see through it to the back of the reflector. Showing up on models from nearly all makers, these lights “give the front of the car a more three-dimensional look,” Erion said.
Until the 1980s, there was little car designers could do to improve a headlight’s output or looks because headlights, according to lighting engineers, were the most regulated part of a vehicle. Cars made for sale in the U.S. had to meet stringent guidelines for headlight size, shape, placement and intensity. All lights had to be sealed beams, in which the lens, light and reflector are one unit, and had to be mounted in one or two pairs. A good result of such standardization was that it kept prices down for replacing units.
By the mid-1980s, federal guidelines had been eased. Headlights can now be any shape–as long as the rules governing the lights’ brightness, throw and direction are followed. Ford’s 1986 Taurus was one of the first models to use aerodynamic headlights that were flush with the sheet metal. And headlights no longer have to be replaced as a unit; lights can now use replaceable, brighter halogen bulbs, the kind that have been used by most manufacturers outside the U.S.
The first aerodynamic headlights using replaceable bulbs had a different shape but performed no better than their sealed-beam predecessors. Engineers still needed to find an elegant compromise that would allow them to put enough light in the right places along the road without blinding oncoming drivers. Every time a new headlight shape is created, that process begins anew.
The lighting industry has toyed with a number of solutions to increase nighttime illumination. Manufacturers have experimented with headlights that can reflect ultraviolet light up to twice the distance of conventional lamps, but for such lights to be effective, all road signs would have to be coated with UV-reflective paint.
BMW, Lexus and other manufacturers have tried projection-beam headlights, which use fish-eye lenses to concentrate the light and make it appear brighter.
The state of the art is high-intensity-discharge lighting. Rather than using a glowing filament to create light, HID lamps use high voltage to generate a bluish spark between two electrodes, exciting the xenon gas and leading to the emission of a bluish light.
These headlights create brighter illumination within government standards. Because the light is blue, it appears brighter still. HID lights are still expensive; most are found on luxury cars.
Car models that appeal to older buyers tend to have headlights that throw more light directly in front of the car, said Jeff Mikel, senior vice president of the Guide Corp., a lighting supplier, while those that appeal to younger people will often have headlights that project light a greater distance.
Without computers, it would take weeks of trial and error to create a jeweled headlight. Unlike a regular headlamp, these may have only 20 discernible reflecting facets, so each must be angled precisely to throw the light, Mickel said.
In the next decade, expect to see HID lighting on less expensive cars and the introduction of a light engine, a single lighting source that will transmit illumination via fiber-optic cable to light up headlights, taillights and turn signals.
