What are the benefits of Xenon Headlights?
It doesn’t matter how great your eyesight is or how good behind the wheel you may be, night-time driving can be a stressful experience – especially when you’re tired or when it’s pouring down with rain.
There are few features of a car that can inspire greater confidence at this time than a great set of headlights. Being able to see the road ahead makes it easier to spot possible hazards much quicker, greatly reducing the risk of road accidents.
One of the most common systems used by car manufacturers these days are Xenon headlights. Also called High Intensity Discharge (or HID) headlights, they offer a clean whitish-blue light that illuminates the road far ahead. But how do they work?
The Science Part
Xenon is a chemical element categorised as a noble gas – a group of six chemical elements which are usually clear, odourless and very stable under the typical atmospheric temperatures and pressures.
Unlike a traditional halogen lamp – which emits light due to a huge electrical resistance caused by passing a current through a fine wire (a filament) – the light in a Xenon lamp is produced by an electrical arc jumping from one contact to another. The Xenon gas fills the compartment in which the contacts sit, and amplifies the brightness of the light, helping it to rapidly reach the temperature necessary to emit an intense beam.
In a filament bulb, the constant change in temperature (which caused by the lights switching on and off) will gradually cause the thin wire to become more fragile, and eventually fail (this is when a lightbulb blows). The lack of this filament in HIDs light means that they will generally a longer period of time than traditional bulbs. The light they provide is stronger too, and offers a consistent, clearly defined beam from the front of your car.
Due to their intensity, they can be known to dazzle oncoming traffic, so car manufacturers employ self-levelling systems to stop the light beam from pointing too high. This can be particularly a problem in estate cars, when the back of the car might be weighed down with people and baggage. In many xenon-equipped cars you’ll see the headlight beam skipping about when you first turn the ignition on at night – this is a calibration of the headlights to make sure they level correctly.