Headlight Deterioration Could Leave You Flying Blind

img1981392014 1544482104012 jpg New versus deteriorated headlight on a vehicle | AAA image

Adequate illumination by new-car headlights is getting more attention these days, but you also  should know that if you don’t take care of your headlights, you can end up with up to about 80 percent less light for night driving than you left the dealer lot with, according to new research from AAA.

Related: Report: Headlights Improving, But Most Base Models Still in the Dark

That’s because most headlights are made of plastic, and sunlight can damage and discolor the lights’ protective plastic coatings – which in turn could cut the light you see illuminating the road to as little as 22 percent of low-beam light compared with a new headlight at full capacity. Depending on where and how you use your vehicle, headlights show deterioration as early as three years to five years. AAA urges car owners to do a regular safety check of their lights to look for signs of yellowing or clouding, and to replace the headlights or get the plastic covers renewed. To illuminate the point of why you need to do this, the travel-services provider notes that 50 percent of crashes happen at night.

“Walk through any parking lot and it is evident that deteriorated headlights are a problem for most vehicle owners,” said Greg Brannon, AAA director of automotive engineering and industry relations. “Headlights on the road in the U.S., even when new, don’t produce a sufficient amount of lighting, so any reduction in performance is a real safety issue.”

Researchers measured the potential loss from deterioration by testing the headlights from two popular sedans approximately 11 years in age (about the average age of a vehicle on U.S. roads) and comparing the light from the degraded headlights against new headlights.

Related: Blinded by the Light? Approval for High-Tech Headlights May Help

The good news: It also found that replacing the lights with new ones from the automakers restored performance to 100 percent. Even (often cheaper) aftermarket replacements could restore between 83 and 90 percent; however, these did fall short of certain requirements for light intensity and also were more likely to produce glare for oncoming drivers. An even less expensive option is headlight restoration at repair shops or with do-it-yourself kits; those, too, helped by getting the headlights back up to 70 percent of the new headlights, though that also resulted in more glare. (More details on headlight repair from AAA can be found here.)

Compounding the problem of deteriorated headlights is that many headlights are not that great to start with. The Insurance Institute for Highway Safety has shined the light on headlight quality with new testing since 2016, with evaluations and ratings for each new vehicle that buyers can use as a shopping guide. IIHS notes that the best headlights for a given model often are part of options packages, not on the base model, and that a surprising number of new vehicles still offer no headlight option with adequate illumination. Earlier AAA research came up with similar findings.

So, you need to be particularly sure you are getting the most from whatever headlights you have.

“Driving at night with headlights that produce only 20 percent of the light they did when new, which is already subpar, is a risk drivers shouldn’t take,” said Brannon. “Especially when there are convenient and inexpensive solutions that can dramatically improve lighting performance.”

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Photo of Fred Meier
Former D.C. Bureau Chief Fred Meier, who lives every day with Washington gridlock, has an un-American love of small wagons and hatchbacks. Email Fred Meier

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