When Should You Use Low Beam Headlights?

Proper Use of High Beam and Low Beam Headlights

Why is it important to know when to use high beams and when to use low beam headlights? Well, most of your driving tasks depend on vision and visibility. That is why driving at night and during inclement weather always poses a challenge and becomes more dangerous.

Your ability to see other vehicles, pedestrians, bicyclists, wild animals, or any other obstacles on the road is essential for safe driving.

A description of how to use headlights properly is in your driver’s handbook. It will also (most likely) be one of the items that pop up on your driver’s license or permit test. So, it is a good idea to study the below.

But learning the proper use of your headlights is also very important for your future and daily driving. Improper use may have serious consequences.

You must understand the law even if you have a car with Adaptive Driving Beam (ADB) headlights that automatically switch from high- to low-beam headlights in the presence of oncoming vehicles.

Improper Use of Headlights

A study in Michigan (Insurance Institute for Highway Safety) showed that many drivers don’t turn on their high beams on dark roads, even when they should.

Other drivers may forget they are driving with high beams and fail to dim the lights when they overtake or meet another vehicle.

Both are equally dangerous. I will explain why.

How Much of the Road Can You See Ahead?

Your high-beam headlights let you see about 350-400 feet ahead. Low-beam headlights illuminate the road for about 200 feet, about half the distance.

You should always adjust your speed based on how far ahead you can see. If your stopping distance becomes farther than you can see with your headlights, you are over-driving your headlights. If you overdrive your headlights, you cannot stop in time if there is an obstacle in your way.

When you travel 35 mph at night, it takes roughly 200 feet to bring your car to a complete stop on a dry pavement. If you travel faster on a dark road with your low beams on, you are driving blind and risk a severe crash. Even if you react quickly and hard braking slows your vehicle, hitting a pedestrian at 25 mph is likely to get the pedestrian killed or seriously injured.

If you want to drive faster on a rural road with no oncoming traffic, you must turn on your high beams (read more about when to use high beams).

Why Can’t You Use High Beams All the Time?

It would be ideal if you could always drive with your high beams on since they let you see farther ahead.

So, why can’t you? The reason you cannot do this is that high-beam headlights cause glare. You can blind oncoming drivers or drivers in front of you.

Bright lights in the field of view reduce a driver’s ability to see, create intense discomfort, or both. When driving at night, glare is often caused by viewing headlights from oncoming vehicles or headlights in your rearview mirrors.

When your eyes encounter glare, it becomes harder to see ahead. Your reaction time increases when exposed to glare and even after the exposure. The glare has a lasting effect on your eyes since it takes time for your eyes to recover their ability to see normally.

When You Must Dim Your Headlights

Keeping your headlights on high beams when you meet oncoming vehicles or approach another vehicle from behind causes glare and may blind other drivers.

Consequently, the law requires you to dim your high-beam headlights at a certain distance from other drivers. The distance is usually set to 500 feet when you meet an oncoming vehicle and to 300 feet when you are approaching another vehicle from behind. The law has set the distance based on how far high and low-beam headlights reach and when they may become a problem for others.

Manufacturers have designed high-beam headlights for use in dark areas and when traveling at higher speeds. You should typically avoid using them when you drive in cities and towns.

Dim your headlights when driving in lighted areas with pedestrians, bicyclists, and other vehicles around. You should also adjust your speed so you can stop within the distance you can see ahead.

Blinding Yourself with Your Own Headlights

High beams also create problems when driving in bad weather, such as rain, snow, or fog. Only some light passes through the water drops, while the rest scatters. Some reflect to your eyes. This reflection of your headlights reduces the contrast of everything in your field of view and creates a glare, impairing your vision.

Turning on your low beams will reduce the scatter and the reflection, causing less glare. In most cases, low beams will also let you see the road better in poor weather conditions.

Can I Drive With Low Beams During the Day?

Studies have shown that using low-beam headlights during the day reduces the risk of head-on collisions by over 20%.

Automatic daytime running lights help, but they typically don’t illuminate your tail lights. Therefore, they should not be confused with headlights.

Note that some states require you to use low-beam headlights whenever you drive in a work zone.

How to Use Low Beam Headlights Properly – a Summary

The light from beam headlights may cause glare. That is why you must use low-beam headlights when you meet oncoming vehicles or approach another vehicle from behind. Using low beams in lighted areas like cities is also a good idea. You should also use low beams when driving in fog, heavy rain, or snow to avoid blinding yourself.

Remember to Slow Down

Remember, you must slow down when you drive in bad weather and with only your low-beam headlights turned on. You must also increase the following distance since you cannot stop quickly.

Never overdrive your headlights, and always keep a safe following distance.

30 Minutes After Sunset – 30 Minutes Before Sunrise

Most states require you to use headlights 30 minutes after sunset and until 30 minutes before sunrise. It is a common mistake to think it is the other way around (30 minutes before sunset and 30 minutes after sunrise). If you understand when darkness occurs, you also understand why lawmakers wrote the law this way, and the rule is easier to remember. Learn about civil twilight and when to turn on headlights here!

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Top illustration copyright: whilerests, second illustration adaption by driver’s Prep based on a photo by andreiuc88

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