High beam headlights allow drivers to see potential obstacles that might otherwise not be illuminated. Every state has rules that regulate the use of high beams, including when you should lower them to avoid dazzling other drivers. Generally you should dim them within 500 feet of an oncoming car.
When traveling late at night down dark roads without sufficient illumination, many people click on their high-beam headlights, also called brights. They allow drivers to see potential obstacles that might otherwise not be illuminated. High beams also help drivers feel more secure in their surroundings while they navigate the road, and are a safety feature designed to help everyone drive more responsibly. Every state has rules that regulate the use of high beams.
Effects on Other Drivers
The exact distance varies from state to state, but generally you are required to lower your high beams when you come within 500 feet of an oncoming vehicle. When you approach a car moving in the same direction, lights need to be dimmed within approximately 350 feet. Generally this is also true when approaching people or other significant objects. You are allowed, however, to remind other drivers to dim their high beams by quickly flicking your brights on and off.
High Beams in the Dark
In dark areas, you can see three times as far when you turn on high beams. Most states require that you use high beams in remote or excessively dark areas where it is impossible to see the road otherwise. By contrast, low beams should be used in the fog because high beams will be reflected back at you, essentially obscuring your ability to see.
Dangerous Lighting and Headlamps
In most states it is a violation when a driver fails to dim headlamps, which can cause "dangerous or dazzling" light visible 75 feet or more ahead of such lamps. This applies to aftermarket halogen lights that are super-bright and often used as high beams. Additional lights that can be illegal are flashing lights designed to make others believe your car is a police vehicle.
Penalties for High Beams
The penalties for improper high-beam usage will vary from state to state, but is usually a fine that can range between $35 to $75 and increasing with each subsequent offense.
In most states, if you drive with high beams on because one of your headlights has burned out, you are actually breaking two laws. It is illegal to drive with a burned-out headlight, and it is not a legal alternative to assume that it is safer to be able to see the road using your brights because you can't see as well with only one functioning headlight.