

When to Use Your Car's High-Beams

Here's how to make them work for you the way they were designed to.

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We're here to, ahem, shed some light on when to use high-beams. Of course, they're great for when you want to see more of the road ahead at night. But when to use high-beams involves more than that: There are several useful, time-tested rules for better use of your vehicle's lighting system. Follow them and you'll be a safer driver, possibly sidestep the ire of other road users—and maybe even avoid a moving violation for temporarily blinding the drivers of oncoming cars.

The headlights in your vehicle have two modes: low-beam and high-beam. The low-beam mode produces a less intense light that provides a nighttime down-the-road view of about 200 to 300 feet, or the approximate length of a football field. It may seem like a lot, but if you're traveling at 60 mph, it takes just 3.4 seconds to cover that distance. Your high-beams, which are typically activated either by pushing or pulling the turn-signal stalk, are more powerful: They project light about 350 to 500 feet, depending on your lighting system's specifications.

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What High-Beams Can and Can't Do

Isn't more light always better for nighttime safety? Why not simply leave your high-beams on and enjoy the brightest, longest-range view? First, high-beams are actually less effective in certain weather conditions. And second, it's not safe, because we share the roadway with other drivers.

While you see more and farther under most conditions in high-beam mode, your powerful blast of light actually reduces the visibility of oncoming traffic (sometimes for a significant interval of time). This situation is like staring into a flashlight in a dark room. You can see the blazing light but little to nothing else around it. Imagine traveling on a dark two-lane road at 50 mph with oncoming traffic. The closing speed between the vehicles is approximately 100 mph. And the closer the vehicles get to each other, the less the surrounding area and other traffic are visible.

Has this ever happened to you? If so, you know how important it is to know when to use your high-beams. The intense oncoming light is painful to eyes and mentally discomforting; you simply can't see much for a couple of precious moments. And second, motor-vehicle laws in most states require you to switch off your high-beams and refrain from flashing your high-beams within 500 feet of other traffic.

Should You Flash Your Lights?

But what if another driver fails to dim their brights? Most driving manuals recommend focusing your eyes on the right shoulder and its white line as you pass. Why not vigorously flash your high-beams at them? Flashing, unfortunately, is an ambiguous form of communication. Are you angry, being rude, or warning others about a speed trap, a deer crossing the road, or an accident behind you? Flashes are easily misinterpreted by other motorists—and police. Although Florida has ruled that flashing your lights is a form of free speech—Michigan ruled it's also legal to flip off an officer—law-enforcement in other states may consider flashing your lights a reason to pull you over.

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When to Use High-Beams and When Not to

If, however, you're on the highway or a lonely rural road with no traffic within 500 feet, go ahead and blast the high-beams for better visibility. Their extra range makes higher-speed driving safer, because you can see farther ahead. There's less chance of "overdriving your lights." But also be aware that your brights can reduce the visibility of and annoy drivers in cars you are following, as your brights are reflected off their rearview mirrors and into their eyes. So as you catch up to cars ahead, dim your high-beams as a courtesy.

As to the effects of weather, keep in mind that in rain, fog, or snow, low-beams often provide better visibility. That's because high-beams are aimed higher, plus their brighter light bounces off the fog, raindrops, or snowflakes suspended in the air as if they were millions of tiny mirrors. The light is reflected into your eyes rather than down the road, reducing your visibility. In the higher-density traffic and lower speeds of urban and suburban streets, the low-beam setting gets the job done and reduces the possibility of making other drivers and police uncomfortable. (Properly designed and aimed fog lamps with even lower cutoffs can theoretically do a better job in fog, snow, or rain than low-beams, but the truth is that most vehicles' fog lamps are designed more for show than effective lighting.)

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So be smart and considerate. Keep your beam use straight: low for lower speeds, suburban areas, and rain or fog. High for higher speeds and highways, but only when you can maintain at least 500 feet between your vehicle and the rest of us. And thank you for doing so.


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