Want this question answered?
If you can see the area lit by their headlights, then you are probably close enough to dim your own.
300 feet
500 feet if the vehicle is coming to you, 300 feet if you are following it.
Common courtesy would be at least 500 feet.
You should dim your headlights within 500 feet of the car in front of you. The rule of thumb is, if you can see another car, dim your lights.
never
Headlights should not be left on while the vehicle is not in use. If you are not driving, you will just drain your battery while having your headlights on.
100 yards
At night a driver should dim his headlights when an oncoming motor vehicle comes within 1,000 feet. You should switch your headlights from full beam to dipped beam when a oncoming car passes. It is unsafe to leave your headlights on full beam as it blinds the driver of the oncoming car.
Dim headlights form high beam to low beam
At night a driver should dim his headlights when an oncoming motor vehicle comes within 1,000 feet. You should switch your headlights from full beam to dipped beam when a oncoming car passes. It is unsafe to leave your headlights on full beam as it blinds the driver of the oncoming car.
Keep your headlights on low beam.