Why good headlights are essential

Driving at night is dangerous—more so than most people realize—because a driver’s ability to see things clearly at night can be reduced by as much as 60%, according to AAA. If you think that’s an exaggeration, check out these stats from the Insurance Institute for Highway Safety (IIHS) and the National Highway Traffic Safety Administration (NHTSA):

• About 25% of automotive travel takes place at night, but more than 50% of driver fatalities occur then (NHTSA).
• About 77% of pedestrian deaths happen after dark (NHTSA).
• More than 25% of fatal crashes occur on unlit, rural roads (IIHS).

Good headlights are vital to safe driving at night. They’re a primary safety system—your first line of defense against injury, death, or damage to your vehicle. Unfortunately, the quality of headlights on cars sold in the U.S. isn’t uniformly good.

Headlight development in the U.S. has wallowed in the Dark Ages for decades, lagging behind that of Europe and Japan because of outdated regulations. The principal challenge is to make headlights bright enough so that drivers can see and avoid objects on the road, and at the same time not create glare for other drivers.

But for years, many automakers seemed to consider headlights as an afterthought, not as a key safety feature, according to IIHS. As a result, entry-level and lower-priced cars have often been equipped with less-effective headlights. Fortunately, that’s changing.

The reason effective headlights matter is simple physics. At 60 mph, it may take more than 300 feet to see an object in the road, process the information, and bring your car to a stop, according to testing by Consumer Reports. And the faster you drive, the longer it takes.

But, according to AAA, the low beams on halogen headlights might light up the road for only about 300 feet, which means drivers can easily “outrun” their headlights. In fact, a AAA study determined that many low beams provide adequate lighting for speeds of only 39 mph to 55 mph.

Three types of headlights can be found on U.S. cars today:

•  Halogen headlights have been standard issue on vehicles since the 1960s and today are found mainly on lower-priced vehicles. Halogen headlights typically have a low-beam range of about 300 feet and a high-beam range of just over 400 feet.
• High-intensity discharge (HID) headlights were introduced in the 1990s. Their effective range is about 400 feet on the low-beam setting and about 500 feet on high beams.
• Light-emitting diode (LED) headlights first appeared on cars in the early 2000s. Their effective range is about 450 feet on low beams and about 500 feet on high beams. These days, automakers are equipping more and more of their vehicles with LED headlights.

On average, high beams provide about 28% more illumination than low beams, according to AAA. So, plugging in the numbers, it’s clear that if cars drove with their high beams on more often (especially if they have HID and LED headlights) they’d be able to see much farther down the road and would be less likely to outrun their headlights and become involved in a crash.

But there are 2 problems with this scenario. The first is that, even when it would be beneficial and safe to do so, nearly two-thirds of motorists who drive at night say they don’t regularly use their high beams, according to AAA research. Second, driving with your high beams on can blind other drivers.

Fortunately, a huge change is on the horizon. A provision in the 2021 federal Bipartisan Infrastructure Law permits cars in the U.S. to use adaptive driving beam (ADB) headlights, which have been legal in other countries for more than a decade.

 ADB headlights always operate on a high-beam setting for maximum visibility. But, using cameras and software, they continuously adjust the shape, direction, and intensity of the light pattern to create a “shadow” around vehicles that might be affected, effectively eliminating glare for those drivers.

AAA compared headlight performance on U.S. cars with that of ADB headlights found on some European and Canadian cars. After testing ADB on a closed course and public roadways, AAA concluded that in real-world traffic conditions, ADB lighting systems provide as much as an 86% increase in roadway lighting. At the same time, on average they produce no more glare than standard low beams.

Widespread use of ADB headlights will improve pedestrian and bicyclist safety by making them more visible at night, according to NHTSA. It will also prevent crashes by better illuminating animals and objects in and along the road.

No vehicles currently sold in the U.S. are equipped with ADB lighting. “We think it will be several years until we see ADB on U.S. roads,” says Joseph Young, director of media relations at IIHS. “It isn’t as simple as automakers swapping out headlights for the ADBs that they’re already using in Europe, because the specifications are a bit different.”

Until ADBs arrive, if you’re shopping for a new car, LED headlights generally provide the best illumination. But the specific technology isn’t the only consideration. As IIHS says, “Use of a particular technology does not guarantee a good rating. Similarly, there are examples of poor ratings for every type of headlight.” Factors such as headlight design and proper aiming of headlights matter, too.

As part of its safety testing and vehicle-ratings programs, IIHS evaluates the effectiveness of headlight systems in different driving situations, and the agency factors visibility and glare into its ratings. “Drivers can reduce their crash risk by selecting a vehicle with one of the best headlight designs,” says Matthew Brumbelow, a senior research engineer at IIHS.

IIHS found that single-vehicle crash rates were nearly 20% lower and pedestrian crashes were 23% lower for headlight systems that earned a “good” rating than for those with a “poor” rating. Also, “good” headlights reduced the risk of crashes in which a driver was injured by 29%. To receive the IIHS coveted Top Safety Pick award or its Top Safety Pick+ award, vehicles for the 2023 model year must have headlights rated either “acceptable” or “good” as standard equipment.

Vehicle lighting is rapidly improving. More than 40% of the model-year 2023 vehicles IIHS tested earned a “good” rating, and only 5% had excessive glare. You can find a vehicle’s headlight rating at the agency’s website. Just enter the vehicle model in the search box and scroll down to “Headlights.”

Here are some things you can do to maximize your safety when driving at night:

• On unlit roadways, use your high beams whenever it’s safe to do so—that is, when it wouldn’t risk blinding other drivers.
• Carefully monitor your speed to avoid hitting pedestrians, cyclists, animals, or other objects on the roadway.
• Make sure your headlights are aimed properly so they don’t create glare for other drivers. Have your dealer or repair shop check them annually.
• Make sure your headlight lenses are clean.
• Cloudy or yellowed headlight lenses transmit only a fraction of the light of new headlights, making for dangerous nighttime driving. You can easily restore cloudy lenses to almost full effectiveness with an inexpensive kit from an auto parts store.
• To avoid glare from oncoming cars’ headlights, shift your gaze to the white line on the right of the road until the cars pass.
• When you buy a new car, check the type of headlight it’s equipped with and look up the IIHS rating. Take a nighttime test drive for a real-world headlight assessment.
• Automatic headlights, available on an increasing number of cars, automatically turn on and off in response to the amount of ambient light. They’re a useful safety feature for drivers who forget to turn their headlights on.
• Automatic high beams improve driver visibility and reduce crashes, especially on unlit roadways. With this feature, high beams are the default setting, and the system switches back to low beams automatically when high beams might create glare for drivers of nearby cars.
• Self-dimming rearview mirrors minimize glare from the headlights of cars behind you.
• Curve-adaptive headlights, which swivel with the turning of the steering wheel, make it easier to see around corners.

For more information on headlight performance, go to the AAA Newsroom.

The Automotive Research Center is a state-of-the-art test facility in Los Angeles that has been performing emissions, fuel economy, and safety tests on vehicles for more than 50 years.