You are driving a 40-foot vehicle at 50 mph. Driving conditions are ideal (dry pavement, good visibility). What is the least amount of space that you should keep in front of your vehicle to be safe?

The following distance is calculated as one second for ten feet of vehicle length, plus an extra second if you are moving faster than 40 mph. As a result, for a 40-foot vehicle going at 50 mph, the following distance of 5 seconds should be left.