Under good conditions, when driving behind any vehicle, at any speed, you should

Drive as close to the vehicle in front as possible
Stay at least three seconds behind the vehicle in front of you
Stay one second behind the vehicle in front of you
Explanation: Calculating this rule is fairly simple. Basically, you should always allow three full seconds between yourself and the vehicle in front of you. You can do this by using a specific point ahead such as a sign that you see on the side of the road, and then count “one-thousand-one, one-thousand-two, one-thousand-three.”

