A new AAA report found that as your car's headlights age, the amount of light they produce for a dark drive is significantly diminished.
The AAA report found that clouded or yellowed headlights, when used on low beam, provided 22 percent of the amount of light a new headlight does.
“Headlights become yellow and cloudy over time because of the sun,” said Amy Parmenter, spokesperson for AAA of Greater Hartford.
AAA said exposure to sunlight breaks down the plastic coating on headlights, causing discoloration that obscures the amount of light produced. AAA said depending on where and how the vehicle is used, headlights can start showing signs of deterioration after three to five years.
Parmenter said about half of all crashes happen at night, highlighting the importance of good headlights.
"One of the most important things when you're driving is that you can actually see where you're going and see any danger that might be ahead," she said.
The Insurance Institute for Highway Safety (IIHS) started testing headlights in 2016.
An IIHS report released in November found, “For the 2018 model year, the best-available headlights on 32 of 165 models evaluated earn the highest rating of good, and the best-available headlights on 58 models earn the second-highest rating of acceptable. Thirty-two models have only marginal-rated headlights, while poor-rated headlights are the only ones available for 43 models.”
In many cases, the IIHS found the better headlights are only available on more expensive trim levels. LED and high-intensity discharge (HID) performed better than traditional halogen headlights in the IIHS tests.
"So we know that the new headlights are already relatively insufficient and then you add to that this cloudiness or the yellowness that limits the headlights even further," Parmenter said.
For the best light output, AAA recommends replacing deteriorated headlights with original equipment manufacturer (OEM) parts. Parmenter estimates that would cost up to $400 depending on your vehicle.
AAA found aftermarket parts also performed well, restoring light output between 93 and 90 percent. However, AAA said the aftermarket parts failed to meet certain requirements for light intensity, and were more likely to produce glare for oncoming traffic.
Headlight restoration is a more cost-effective method, according to AAA. But it is also offers less of an improvement in light output than replacement. AAA said professional and do-it-yourself restoration returned light output to approximately 70 percent. Restoration also produced the most glare.