Explanation

"On a busy motorway, traffic may travel at high speeds despite the vehicles being close together. Don't follow too close to the vehicle in front. If a driver directly behind seems to be too close to you, increase your distance from the vehicle in front by slowing down gently. If the traffic in front slows, you'll be able to spread your braking over a longer distance. This will reduce the risk of the driver behind being unable to stop in the room they've allowed."