As you likely know, headlights come in two beam patterns - high and low. High beams emit an intense, widespread light meant only for unlit, empty roads as they can blind other drivers. Low beams direct a narrower zone of light straight ahead to brightly light up what's in front of you without the glare.
Using the proper headlight setting is not only safer for you and your passengers but also courteous to drivers and pedestrians sharing the road.
In this article, we'll dig into the specifics of high beam vs low beam headlights, so you know exactly which mode is appropriate for varying driving conditions.
What Are High Beam Headlights?
High beam headlights, also known as "main beams" , “full beams”or "brights," are the more powerful of the two types of headlights. Their main purpose is to cast a strong, focused beam of light that illuminates the road ahead when visibility is poor, like on a dark country road.
High beams give you the best possible view of the road at night when there are no other vehicles around. While your low beam headlights are perfectly adequate for most nighttime driving, high beams maximize your visibility to avoid surprises. The more you can see, the more time you have to react to any hazards.
How exactly do high beam headlights work? It comes down to the combination of high-output bulbs that emit more light, and the optimized lenses and reflectors that focus and direct that light down the road. When you flip on your high beams, a relay triggers to send extra power to those bulbs so they can shine brighter.
What Are Low Beam Headlights?
Low beam headlights, also called “dipped beams” or “dimmed beams”, are the standard lights you use when driving in most situations.
The function of low beam headlights is to provide enough light for safe nighttime driving while also being conscious of other motorists. When you turn on your low beam headlights, they emit a more dispersed and less intense beam of light compared to high beams. This light is angled downward, illuminating the road ahead without blinding other drivers.
While drivers used to have to switch on their low beams manually, newer vehicles are able to activate them automatically by sensing when the ambient light levels drop, such as after sunset or when pulling into a dimly lit parking area.
Should I Use Low Beam Or High Beam?
High beams are meant for those really dark, isolated roads with little to no traffic. If there are no other vehicles around and you're having trouble seeing the details of the road ahead, go ahead and flip on your brights. Just be sure to switch back to low beams when you see headlights coming towards you from far away. We don’t want to blind oncoming drivers! For more information on this subject, here's an article about when to use high beams.
For normal nighttime driving on main roads or any time there are other vehicles around, low beams are the way to go. Low beams cast light far enough down the road for safe driving at lower speeds but won’t glare in other drivers’ eyes. Save the high beams for the back roads.
Don't forget to actively switch between high and low beams when traffic conditions change. Nothing is more annoying to other drivers than leaving your high beams on when there are other vehicles around! And of course, for safety's sake, dim your beams when following behind other vehicles or if another car overtakes you from behind.
More Differences Between High Beam and Low Beam
In addition to their function and uses, let’s take a deep dive into the nuances between high abd low beam headlight settings.
Operation
The low beam light is automatically on when you turn on your headlight.
In older cars, high beams are usually operated by a foot switch in the floor, just to the left of the brake/clutch pedal. On newer vehicles, the high beam controls are located on the steering signal lever.
Symbol
The high beam indicator light on the instrument panel lights up when the high beam is on. The high beam symbol is a blue symbol with five horizontal lines stacked vertically to the left in a shape similar to the headlamp. When the high beam is turned off, this symbol is also turned off.
The icon for the low beam is the same as high beam, but the lines protruding at a slightly downward angle.
Beam Pattern
Beam pattern refers to the shape of the light on the road. High beams cast a wide, far-reaching beam to maximize how much of the road you can see. Low beams have a more focused beam that illuminates the road right in front of you and off to the side a bit.
Brightness
Brightness is fairly self-explanatory. High beams are meant for those pitch black nights and activate your headlights’ maximum brightness. Low beams are dimmed for normal night driving so you don't blind other drivers.
The Angle of Illumination
It refers to how much the beam slopes relative to the road. Because high beams need to project far ahead, they have a higher angle. Low beams have a lower angle suited to shorter ranges.
Range of Illumination
How far each beam reaches down the road depends on your specific headlight bulbs, but high beams typically illuminate 300 to 500 feet ahead, while low beams handle 100 to 200 feet for safe driving.
Legal Requirements for Using High and Low Beams
Most places require the use of low beams when following within 200 feet of another vehicle, or when meeting traffic coming towards you. High beams should only be used when alone on dark roads. Failure to follow these rules of the road could earn you a traffic ticket or worse.
How to Switch from Low Beam to High Beam?
It's always a good idea to make sure both sets of lights work properly and manually switch from low to high beam light as needed.
Different makes and models of cars have different ways to switch from low light to high beam and back. In most cases, the mechanism is built into a lever next to the steering wheel to turn the headlights on and off.
To switch from a close light to a high beam, simply push the blinker lever away from you. You can feel the click to be sure that the high beams are turned on. If you want to turn off your high beam, you can pull the blinker lever towards you until it snaps into place.
Are There Two Different Bulbs For High And Low Beams?
The answer depends on your specific vehicle make and model. Some cars use the same bulb for high and low beams (Dual-beam system), while others have dedicated bulbs for each beam option (Siga-beam system).
Dual-Beam Headlight Systems: One Bulb, Two Functions. Most modern cars have adopted a dual-beam headlight system, which means that a single bulb on each side of the vehicle has two filaments to serve the purpose of both low and high beams. (Common dual-beam headlight bulb sizes include 9003/H4, 9004, 9007）
Single Beam Headlight Systems: A Separate Bulb for Each Beam. In older vehicles and some specific models, you may find single beam headlight systems that use two separate bulbs for high and low beams on each side of the car.
If you have a vehicle with this single beam system, you'll need to buy two sets of bulbs when replacing or upgrading your headlights – one set for low beams and another for high beams. For example, 9005/HB3+H11/H9/H8 package, 9005/HB3+9006/HB4 package are popular options for many vehicles’ headlight upgrade.
How to tell?
If you've got two distinct headlight elements or assemblies on each side, chances are you've got separate high beam and low beam bulbs. But if there's only one headlight element per side, you probably have dual filament bulbs that handle both high and low beams. Either way, your owner's manual is the best source of truth for specifics on your model.
Frequently Asked Question (FAQ)
Can you use high beam bulbs for low beam?
With little tinkering, it is possible to do this procedure, but it is strongly recommended that you do not perform it. It is better to use the correct bulb for the socket.
Are high beams actually brighter than low beams?
Yes. The high beams bulb will produce a greater amount of light due to the position and angle it placed within the headlight.
Are high beams legal?
Yes. The use of high beams is legal, but should not be continued as they can blind other drivers. Use of high beams should be limited to very dark environments with little oncoming traffic.
Should I use high beams in rain, snow or fog?
Not recommended. You should switch to a low beam light. This is mainly because water molecules reflect light from high beams. This, in turn, will make it harder for drivers to see the road clearly. Water patches usually blur everything in front of you.
Final Thoughts
To summarize, high-beam and low-beam headlights serve distinct purposes with different characteristics. Understanding how and when to properly use each is critical for safe driving in low light.
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