Commercial Driver License (CDL) Class B Practice Test

If driving a 30-foot vehicle at 55 MPH, how many seconds of following distance should be maintained?

1. Three seconds

2. Four seconds

3. Five seconds

4. Six seconds

The correct answer is: Five seconds

Maintaining a safe following distance is crucial for the safe operation of a large vehicle, such as a 30-foot vehicle. The guideline for determining the following distance is often based on the speed of the vehicle. A commonly recommended practice is to maintain at least one second of distance for every ten feet of vehicle length. In this case, you have a 30-foot vehicle traveling at 55 MPH. Following the guideline, you would multiply the vehicle length by the appropriate factor for speed. Since the vehicle is 30 feet long, a three-second rule would not provide sufficient space to react in emergency situations, especially at 55 MPH. On the other hand, increasing the following distance to four seconds is advisable in normal driving conditions. However, at higher speeds, such as 55 MPH, you may need to allow for more time to react due to increased stopping distance and reaction time. This makes five seconds an even more prudent choice, particularly given the potential for sudden stops or hazards on the road. Ultimately, the recommendation of maintaining a six-second following distance for a 30-foot vehicle traveling at 55 MPH is aimed at ensuring adequate time to react to unforeseen circumstances, providing a buffer that enhances overall safety. This extended distance allows for