What is considered a safe driving distance for commercial vehicles on highways?

The correct answer is based on the guideline that safe following distance for commercial vehicles should take into account the length of the vehicle. For every ten feet of vehicle length, maintaining at least one second of distance is crucial. This rule allows drivers to have adequate time to react to sudden stops or emergencies and is particularly important for large vehicles that require more time and distance to stop safely.

Commercial vehicles are typically longer and heavier than passenger vehicles, necessitating greater caution to avoid collisions. By measuring the following distance in seconds rather than fixed distances like feet or car lengths, drivers can adjust their following distance based on their actual speed and conditions, which vary across situations. This significant time buffer enhances the driver's ability to respond to unexpected changes on the road.

The other options suggest either fixed distances that do not account for vehicle size and weight dynamics or distances that are inappropriate for the operating characteristics of a commercial vehicle. Effective safe driving practices are essential for maintaining safety on the roads, particularly for larger vehicles that interact with smaller traffic.