Keeping a gap from the vehicle travelling in front of you is necessary:

1. ATo prevent a front-to-rear collision, when the vehicle in front of you stops or slows down.
2. BIn order to drive in the correct lane and at the correct speed.
3. CAt high speeds only and in stormy weather.
4. DOnly when the vehicle's driver is very tired and his reactions are not fast enough.

Pick an answer to test yourself