What is the requirement for maintaining an assured clear distance when following another vehicle?

Maintaining an assured clear distance when following another vehicle is crucial for safe driving. The requirement focuses on ensuring that a driver has enough distance to safely stop their vehicle without colliding into the one in front. This distance takes into account multiple factors, including speed, road conditions, and the stopping capabilities of the vehicle.

By ensuring sufficient space to stop, a driver can react to sudden stops, obstacles, or changes in traffic without the risk of an accident. This principle is foundational for defensive driving and is particularly important in preventing rear-end collisions, which are among the most common types of accidents on the road.

While the other options suggest fixed distances such as one or two car lengths or distances based on vehicle size, these do not adequately account for varying speeds and conditions. The focus should always be on safety, which is why the appropriate answer emphasizes the ability to stop without collision.