Re: Why do some cars use Xenon gas lights, and how do they affect visibilty?

Greetings:

Most of the lamp manufacturing companies have information about headlamps 
on their web pages. Most of the information that I have presented comes 
from the Phillips web site at the following URL:

http://www.eur.lighting.philips.com/automotive/


Following are the answers to your questions along with several more 
frequently asked questions and technical bits of information.

Why do some cars use Xenon gas lights?

No less that 60% of all traffic accidents take place in poorly lit 
conditions. Therefore, lighting greatly contributes to road safety and 
comfort. It is a fact that the elderly require more light than the young (a 
person aged 60 requires up to ten times more light than a twenty
year-old). Due to the strong increase of the ageing population and the fact 
that the elderly wish to remain mobile, we have seen an increase in the 
number of elderly motorists,  who require more light to drive safely.


Is is more efficient?

The xenon bulb provides more than twice the amount of light of a halogen 
bulb, while only consuming half the power (wattage). Therefore, the driver 
can see more clearly, and the car has more power for other functions. 
Moreover, it is environmentally friendly, as less power means less fuel 
consumption. The clear blue - white light produced by the xenon bulb is 
actually more similar to daylight than conventional yellowish lamps. 
Research has shown that this enables drivers to concentrate better. 
Furthermore, this particular light color reflects the road markings and 
signs better that conventional lighting. The xenon bulb also delivers a 
marked contribution to road safety in the event of limited visibility due 
to weather conditions. 

Do they have a long life?

In practical terms, the life span of the bulb is equal to the LIFE OF THE 
CAR, which means that the bulb need never be replaced unless they are 
damaged by accident.

Do they work better or blind oncoming drivers?
 
In normal circumstances drivers look straight ahead, however, due to the 
conspicuous color of Xenon Light, drivers are more inclined to look into 
the headlamps. The same phenomenon was experienced during the introduction 
of halogen headlamps in the Sixties. In those days people also spoke of 
'that irritating white light'. The introduction of Xenon headlamps will 
therefore  entail a period becomming accustomed to the lights, similar to 
those experienced during the introduction of halogen headlamps, yellow turn 
indicators and a third high mounted brake light.

Doesn't the use of Xenon Light cause more irritation among oncoming 
drivers?

The international regulations governing light distribution and intensity on 
the road are very strict. Xenon Light falls well within these boundaries. 
Technically speaking, xenon lighting is less irritating than conventional 
light. As the light-darkness borders are much more clearly defined, less 
light is reflected into the eyes of oncoming drivers. The increased amount 
(double) of light produced is mainly used to achieve higher intensity and 
better distribution of light on the road. Moreover, the road edges are also 
better lit. 

Technically head lamps must meet 3 conditions that are contained in the 
international regulations concerning the use of Xenon Light:
 - The headlamps must be aligned according to regulations. 
- The vehicle must be fitted with an automatic headlamp levelling system, 
so that when the load is increased the headlight beams are automatically 
adjusted. 
- The headlamp must be fitted with an automatic cleaning system, as dirt 
deposits on the lens act as a diffuser, thereby projecting the light beyond 
the prescribed range. 

These three conditions together with the extensive life span of the xenon 
bulb greatly reduce the risk of incorrectly aligned headlamps. The use of 
halogen bulbs entails a much higher risk.

Can't halogen bulbs be improved on?

The limits of halogen bulb technology were reached with the introduction of 
the premium halogen bulb, which produces 30% more road light than the 
standard halogen bulb. Further opportunities for a breakthrough entail 
entirely new technologies. The gas discharge bulb has proved to be the 
answer.

Why is Xenon Light so expensive?

Xenon lighting is not simply a question of a new type of bulb, but a whole 
new, life of the car  system consisting of: 

 A highly complex and hi-tech bulb, manufactured according to the highest 
standards of precision. 

- An electrical ballast and electric starter. The manufacture of the 
ballast in particular requires complex
technology. 

- Automatic headlamp levelling and cleaning systems. 

The price is governed by all these components. As soon as Xenon Light 
achieves wide-scale application, the price will drop. However, it will 
remain substantially more expensive than the halogen headlamp. Therefore, 
we should not view Xenon Light as a replacement for halogen bulbs, but as a 
hi-tech system for the improvement of road safety and the comfort of 
drivers and other road users. 


Best regards, Your Mad Scientist

Adrian Popa