You are traveling at 35 mph in a 40-foot vehicle. The road is dry and there is great visibility. What is the smallest spacing in front of your car that you should maintain for safety?

The formula for following distance is one second for each ten feet of vehicle, plus an additional second if you're traveling over 40 mph. As a result, you need to provide a four-second following distance for a 40-foot vehicle moving at 35 mph.