What Type of Headlight System is Factory-Installed on Your Car?
When shopping for a new car, look for the model’s window sticker to find out what type of headlight system is factory-installed. Whether it’s halogen or HID xenon, it’s important to understand what you’re getting into.
Ask someone to stand in front of the car and rotate the headlight control dials. Pause at each setting to see how the beams illuminate the ground.
Visibility
Headlamps are the main source of illumination on a vehicle, and their condition and potency can significantly affect how well a driver sees the road at night. One study found that the most common causes of car accidents at night are drunk driving, inadequate visibility, and driver fatigue.
Most cars have both high and low headlamp settings. The low setting (also known as dipped) allows drivers to see where they’re going without blinding oncoming traffic. This setting is especially important in adverse weather conditions like rain, snow, or fog, and just after sunrise or before sunset.
The high-beam setting provides a much brighter light for longer distances, but at the expense of short-range illumination. The brighter light can easily blind oncoming traffic or blind pedestrians, which is a safety risk for both them and the driver of the headlamp-equipped vehicle.
In some countries, it is illegal to drive with the headlamps on high-beam mode at speeds above 60 km/h (40 mph). Headlamps have headlamp car been found to be ineffective for illuminating an assured clear distance ahead when driven at this speed.
Some projector-type headlamps can be adjusted to produce a left or right-traffic low beam by shifting a lever or other movable element in or on the lamp assembly. Other technologies such as adaptive driving beam (ADB) can swivel headlamps between high and low beams automatically based on the steering angle and vehicle speed of the driver.
Safety
The condition and potency of a vehicle’s headlamps can have a direct influence on the safety of the driver and passengers. The primary factors that play a role in nighttime accidents and fatalities are alcohol, driver fatigue, and poor visibility.
In some cases, glare from other vehicles’ headlamps reduces visibility by creating a contrast-reducing “veil” over the visual scene. This is a particularly significant problem on two-lane highways where drivers often have little separation between their own car and the cars of other motorists.
Studies have shown that glare can also decrease visibility by impairing the ability to distinguish between different types of objects. This is known as visual confusion. In many instances, the only effective remedy is to dimmer the other vehicle’s headlamps to avoid glare.
Several manufacturers offer automatic headlamp dimmer systems that relieve the driver of the need to select a low or high beam as driving conditions change. General Motors first offered this feature in 1952 on its Cadillac, Buick, and Oldsmobile models. The system, whose phototube was housed in a gun-sight-like tube atop the dashboard, used a mechanical linkage to switch between a low and high beam.
Various experiments are under way to reduce the glare from vehicle headlamps. A Swedish project called ARENA, for example, has studied the effects of using near-ultraviolet (UVA) headlamps that emit light with wavelengths between 320 and 400 nm. UVA headlamps are able to show road markings and fluorescent clothing very well, but do not pose a health risk because the emission filters prevent the penetration of harmful ultraviolet rays.
Convenience
Some headlamps can switch between low and high beams. The headlamp may be switched by the driver with a manual operation of a switch, or it may be activated automatically based on a running state of the vehicle. In either case, the headlamps produce only the desired beam pattern for a specific driving situation. This eliminates the need to manually switch between headlamp settings and the risk of switching to a setting that will not illuminate the road adequately.
The ability to select between headlamp modes is especially useful on two-lane highways because the lower light levels of two-lane roads reduce a driver’s line of sight and create a much brighter “veil” over the visual scene inside the eye. This effect is exacerbated headlamp car in older drivers, who have more dead cells that increase the amount of scattered light that enters the eye.
To determine the best headlight setting for your car, have a friend stand in front of it while it is parked in a well-lit area. Roll down the window so you can communicate with your helper. Ask your helper to rotate the headlamp control dials through each of the available headlight settings, pausing to look at how the light reflects on the surface of the car. The headlamp dial indicator symbol typically looks like a sun or upside-down light bulb. There is also an enclosed circle next to this indicator that marks the side of the headlamp control dial actually controlling the headlight settings.
Energy Efficiency
A typical set of halogen headlamps uses a tungsten filament in a glass bulb to heat up and emit light, but they’re not very energy efficient. That’s because a lot of energy is wasted in creating unnecessary heat inside the bulb.
LED (light-emitting diode) headlights use semiconductors to transmit energy, emitting photons that create illumination. They require more power than halogen bulbs to start, but they have a longer life span and consume less energy. They’re also much more compact than halogen headlamps and can be mounted closer to the road for better visibility.
Another type of headlight is a HID Xenon system, which uses a special bulb that contains a xenon gas. They need a little more time to warm up before they reach full brightness, but they can produce a bright white or blue glow that’s more natural-looking than traditional headlamps and are up to three times as powerful. They also use less energy than halogen lights and last twice as long.
Some newer headlamp technology shows promise, such as high-beam assist, which automatically applies your car’s high beam when you’re driving alone on a dark stretch of road. But it switches back to low-beam mode when a vehicle comes up behind you, ensuring that other drivers don’t get blinded by the bright beam.