What Are Automatic High Beams?

Photo: Samuel Boivin | Moment via Getty Images

Automatic high beams are a feature on modern vehicles' headlight systems that activate the brighter bulb or "high beam" when the car detects darker-than-usual road conditions. If an oncoming vehicle or better lighting conditions are detected, the high beams automatically shut off and revert to the standard headlight illumination.

How do automatic high beams work?

Most automakers use similar technology to make auto high beams work. Ford, Subaru, and Honda, for example, use a windshield-mounted sensor that detects light to tell the system when high beams can be turned on or off. If the sensor detects an absence of light, it will turn the high beams on. Most manufacturers are betting that the lack of light means there is also a lack of oncoming traffic and that it’s safe for the system to turn on. Inversely, if there’s a lot of light hitting these windshield-mounted sensors, then there must also be oncoming traffic. The goal is not to blind other drivers with our high beams, so the system shuts them off. 

Manufacturers can have different parameters to help their automatic high beams be more effective. For example, Toyota’s version of the feature will recognize not only oncoming headlights but taillights as well so that you’re not blinding a driver ahead of you through their mirrors. Toyota’s system will also only operate above 25 mph so that high beams are not being used in low-speed, potentially close-quarters driving, like in the city, where both cyclists and pedestrians could be blinded. Ford’s will also dim the low beams to reduce glare where necessary, and it too can sense headlights and taillights.

On the whole, automatic high beams are a much better way to manage your headlights for a few reasons. For starters, it can be easy to forget when your high beams are on, especially on dark roads at night. It’s not hard to blind oncoming traffic this way, which is dangerous for both you and the person driving toward you. There are also scenarios when drivers may forget to use their high beams because of ambient light. A lonely but well-lit highway at night is a great example. Sure, there could be more ambient light on the road, but having your high beams on could help drivers detect obstacles farther down the road too.

Potential drawbacks of automatic high beams

While these systems have gotten pretty great at picking up on when it’s safe to turn on high beams, they are ultimately still machines and they can make mistakes. For instance, you may not want high beams on in a parking garage despite a car sensing it is dark enough to have them on. You may also want these functionalities off during bad weather. Anyone who’s driven in a snowstorm knows that hitting those high beams can make things look like “Star Wars hyperspace” without actually enhancing visibility.

How to turn off automatic high beams

Most manufacturers have a simple button near the lighting controls to turn off the auto high-beam function. Usually, it’s the high-beam icon we’ve all seen with an “A” printed inside. For example, to turn off automatic high beams on a Chevy Silverado, drivers simply press the button described above to return to typical high-beam functionality. While other automakers may relocate the button, any new car equipped with the feature will also have a similar method to turn it off.

Despite occasionally needing to be switched off, automatic high beams remain a useful safety and convenience tool for drivers. They’re able to monitor the road while we drive, providing optimal visibility and much-improved safety over conventional manually operated high beams.