Technological advances to the headlamps for commercial vehicles have resulted in longer headlamp life. That, obviously, is a good thing. But with it comes a serious problem that often isn’t given much attention: hazing, crazing/cracking and yellowing.
Regardless of the type of headlamp, they have highly engineered, optically-based light patterns that are specially aimed to give the driver the best view of the road ahead, as well as to prevent discomfort glare to oncoming drivers.
Today’s headlamps are made of hard plastic or polycarbonate resin, covered with a clear film (coating) to protect the surface. Over time, through exposure, this protective film wears away, resulting in hazing, crazing/cracking and yellowing on the headlamp.
These conditions negatively affect the headlamp by diffusing its light output for reduced visibility.
To lessen the effects of headlamp hazing, crazing/cracking and yellowing, properly clean headlamps on a regular basis.
Coatings
There are many coatings available on the market today for headlamps. Make sure, as you consider specifying LED headlamps, that you get a coating that will last as long as the LED light sources.
The Technology & Maintenance Council (TMC) has a recommended practice – RP 171, High-Performance Coatings for Forward Lighting on Commercial Trucks – that provides guidelines for specifying coatings used on headlamps, fog lamps and driving lamps using plastic lenses that are used on commercial trucks. The intent is to increase headlamp service life, improve visibility and ehance safety.
TMC (www.trucking.org/Technology_Council.aspx) is an industry association focused on truck technology and maintenance.
Contrary to some popular opinion, the headlamp restoration process does not return the lamp output to a like-new condition. The headlamps look better but do not produce the same output as a new headlamp.
