Final answer:
The correct following distance when behind a large vehicle or a motorcycle on a high-speed road is at least 3 seconds to ensure safety and allow for adequate reaction time.
Step-by-step explanation:
If you are behind a large vehicle or a motorcycle on a high-speed road, your following distance should be at least 3 seconds. This allows sufficient time for you to react and stop if necessary to avoid a collision. The three-second rule is a guideline that helps maintain a safe following distance at higher speeds. It is crucial to increase this distance if conditions worsen, such as in bad weather, when visibility or traction may be reduced. Understanding and applying safe following distances is an essential part of road safety and can prevent accidents.