500 meters
no
I like to switch around 200-300 feet away from them
You must dim your high-beams if you're within 500 feet of an approaching car and dim your high-beams within 300 feet of the vehicle you follow.
1,000 feet.
If you can see his headlights, drop your high beams. In some states its the law 300 feet at least.
You can use your high beams when it is dark and no one is approaching you and you aren't following anyone.
Should be like any other vehicle. (pull turn signal stick back (high beams on), pull it back again (high beams off).
Dim headlights form high beam to low beam
Be considerate in using your high beams. Your headlights must be on low beam when you are within 500 feet (150 m) of an approaching vehicle, or within 200 feet (60 m) of a vehicle ahead of you, even if the vehicle ahead is in a different lane. You should also dim your lights for pedestrians approaching you. http://www.nydmv.state.ny.us/dmanual/chapter10-manual.htm (Alaska and Oregon are the same as New York - 500 feet.)
Because - as you overtake the vehicle in front, high-beams will be reflected straight back at the driver - through their mirrors. Low beams are angled more towards the ground.
The right side