Commercial Driver's License

Answer: B - In order to calculate the space required in seconds, use the following formula: if you are going less than 40 MPH, use 1 second for each 10 foot of vehicle length. If you are driving more than 40 MPH, use the same formula but add 1 second. In this case, a 60 foot truck would require 6 seconds, but you will need to add an additional second because you are driving more than 40 MPH. Maintaining the proper space between your vehicle and the vehicle in front of you is critical to safe driving and safe braking.