Several reports have circulated recently, accusing headlamps of being ‘too bright,’ especially on modern cars, equipped with High Intensity Discharge (Xenon) bulbs. Complaints about being dazzled by passing vehicles are common but some activists have even started campaigns, intent on persuading the authorities to reduce the intensity of modern headlamps.
Yet, GEM Motoring Assist has argued that too much emphasis is placed upon bulb brightness and not enough of the debate looks at how the light is reflected. Take a rear fog lamp bulb as an example; the bulb is often identical to that used by a direction indicator but the output appears to be more intense, because of factors influenced by the design of both its reflector and lens.
Compared to the traditional halogen bulb, Xenon types provide a more defined headlamp beam pattern, which will increase the risk of glare, should it be directed towards the eyes of oncoming drivers. To prevent this, Xenon lights are required to not only self-level but, to stop road dirt on the headlamp cover from defusing the light, an external washing mechanism has to be provided. This tends to be a built-in jet wash, which operates simultaneously with the windscreen wash-wipe.
Aftermarket Xenon bulb kits have been available to car owners for some years, to serve a desire to make their cars appear more sophisticated, often to the annoyance of other road users. Unknown to many owner-fitters, the reflectors within a halogen headlamp body are incompatible with gas-discharge bulbs, resulting in an improper beam pattern that is more likely to dazzle oncoming traffic. I have come across several suppliers that promote ‘Xenon’s’ advantages for the driver, only to have a small codicil inserted at the bottom of the marketing bumf, admitting that they are not sanctioned by EU Regulations and are fit for off-road use only. I doubt that many purchasers take any heed.
Yet, VOSA’s efforts to monitor the situation seem credible in theory but are difficult to implement in real-time. The inspectorate advises that, because halogen headlamp lenses are incompatible with Xenon bulbs, the entire headlamp unit must be exchanged with a part that complies with ECE Regulation 98 and fitted in accordance with ECE 48. Yet, VOSA admits that no UK Government inspection will take place, to ensure compliance, which makes the whole statement appear worthless.
It seems that the MoT Test cannot be relied upon to take cars off the road either, when they are equipped with Xenon bulbs without compatible reflectors, washers and self-levelling systems. Providing the beam aim and pattern appear to be correct at the time of the test, a pass certificate is likely to be issued. However, within the confines of an MoT test, it is not that easy for an examiner to check the compliance of an aftermarket lamp’s reflector and whether or not the self-levelling system works, or even exists at all.
Xenon bulbs, fitted to incompatible halogen headlamps, are popular DIY conversions but they present a significant safety concern. It is entirely plausible that their propensity to cause glare has led some members of the public to dismiss all Xenon lights as distracting and dangerous to oncoming traffic. Yet, it is not just the brightness of the bulb that is to blame but incompatible reflectors that really cause discomfort. We welcome your views on this contentious subject.