Dim your headlights for oncoming vehicles or when you are within 300 feet of a vehicle:
- That you are approaching from behind. ✓
- Approaching you from behind.
- That you have already passed.
Answer: A. That you are approaching from behind.
Dim your high-beam headlights when you are within 300 feet of a vehicle you are approaching from behind.
Why this is the answer
The California handbook says to switch from high beams to low beams within 500 feet of a vehicle coming toward you, and within 300 feet of a vehicle you are following. A vehicle you are approaching from behind is the vehicle ahead that you are following, so the 300-foot rule applies. The point is to keep your high beams from affecting the other driver while you are close behind them.
Why the other answers are wrong
- B. Approaching you from behind. — A vehicle approaching you from behind is not the vehicle ahead that you are following, so it does not match the handbook's 300-foot following rule.
- C. That you have already passed. — A vehicle you have already passed is no longer the vehicle ahead that you are following, so the 300-foot following rule does not describe that situation.
Remember it
Pair the shorter distance with the car ahead you are following, and the longer distance with lights coming toward you.