This depends on your speed and may depend on what country you live in. Where I live you should travel at a distance suitable for the speed you are traveling.
The rule of thumb is one car length for every 10 miles per an hour that the car you are driving is traveling. For example: You are traveling 70 miles an hour on the interstate, the car you are following should be seven car lengths ahead of you.
What is following distance? Following distance is the space between your vehicle and the vehicle in front of you while driving. It's important for all drivers to maintain a safe following distance, so that they have time to safely stop in case the vehicle in front of them brakes abruptly.
the distance/time in which you should be following at behind a vehicle
Following distance should be increased (more distance) when behind a motorcycle because (1) the MC can stop faster than a car, and (2) it could go down for many reasons. Greater distance decreases the likelihood of running over the MC.
In any driving location, it is generally agreed to be safe if you position yourself 3 seconds or more behind the vehicle in front of you.
When driving, you should always measure your following distance in seconds. A general rule of thumb is to maintain a following distance of at least 3-4 seconds between your vehicle and the one in front of you. This distance allows you enough time to react and brake safely in case of an emergency.
Behind you
They say to be about 3 seconds behind the person infront of you. So the faster you move the further back you should be.
No
20 feet
20 feet
20 feet