Main Content
Highlights
Studies in tailgating
It sounds like a prescription for disaster but on French expressways where cars are travelling at about 95km/h the "most likely gap" between vehicles is 0.5 seconds.
In England drivers prefer a more modest 1.0 seconds; in the US it is likely to be about 0.8 seconds, and in Israel it varies between 0.7 and 1.0 seconds. (In WA the recommended safe gap is 2 seconds)
The examples are given in a study on tailgating by Adelaide University’s Centre for Automotive Safety Research.
According to the centre, experts differ on precisely how great a time gap is needed for "safe" driving but tests have shown it can take a driver between 0.5 seconds and 4 seconds to perceive a dangerous situation and then another second to apply the brakes.
So why are there not more crashes? According to the author, T. P. Hutchinson, it is presumably because drivers look further ahead than the vehicle immediately in front of them and so anticipate whether the vehicle in front will need to slow.
Hutchinson says in most countries "time-headways" of less than a second are regarded as illegal. He suggests numerous ways of increasing the gap but admits enforcement can be difficult.
But he does quote a "futuristic" concept raised recently by the New York University Law Review. It proposed a system by which drivers and pedestrians could award or penalise other drivers with points for good or bad driving.
The resulting tally would be prominently displayed on the vehicle for all to see. (Presumably it would be legible at a distance greater than 0.5 seconds apart…)
