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.
500 feet if the vehicle is coming to you, 300 feet if you are following it.
300 feet
Common courtesy would be at least 500 feet.
A driver should dim their headlights when an oncoming motor vehicle comes within 500 feet. This helps to prevent glare and ensures safety for both drivers. Proper use of headlights is important for visibility and to avoid blinding other motorists.
300 feet
If you can see the oncoming vehicle then he can see you. Dim your lights at that time.
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.
at least 2m
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.
200 Feet
In most states it is 500 Feet. Common sense should prevail.
according to Florida handsbook, you must dim your bright headlights within 300 feet of the vehicle ahead.