Explanation: One way of checking there's a safe distance between you and the vehicle in front is to use the two-second rule. To check for a two-second time gap, choose a stationary object ahead, such as a bridge or road sign. When the car in front passes the object, say 'Only a fool breaks the two-second rule'. If you reach the object before you finish saying the phrase, you're too close and need to increase the gap.
Category: Safety margins
References: The official DVSA guide to driving: section 7, Highway code: rule 126