What is the recommended following distance on an expressway?

The recommended following distance on an expressway is to stay at least two seconds behind the vehicle ahead. This guideline is important because it allows for adequate reaction time in case the vehicle in front of you suddenly stops or slows down. By maintaining a two-second gap, drivers can more effectively assess the road conditions and make safe driving decisions. At higher speeds typically found on expressways, this distance is crucial for ensuring safety and preventing rear-end collisions.

While other options suggest either maintaining a very short gap, such as one second, or a more arbitrary minimum of four seconds in all conditions, neither of these accounts for the variability of traffic conditions and speeds found on expressways. A one-second gap is too close, especially when traveling at higher speeds, as it does not provide sufficient time to react. Conversely, a blanket rule of always staying four seconds back may be overly cautious in certain situations, and may not allow for the fluidity of traffic flow when conditions are safe. Thus, the two-second rule strikes an effective balance for maintaining a safe following distance on expressways.