Tailgaters told to back off

Motorists are being told to back off, with South Australian police catching more than 3000 drivers tailgating last year.

And the RAA has praised police for cracking down on tailgaters, saying it represented justice for those motorists who deliberately and aggressively drive too close and put all road users safety at risk.

Police said the closer a driver is to the car in front the more likely they could be involved in crash with potential serious or fatal consequences.

RAA road safety manager Charles Mountain said drivers tailgated for different reasons.

"Unfortunately you see people who do it deliberately - they may see a green light up ahead and want the car in front to go faster to catch the lights," Mr Mountain said.

"Others will think they can force someone to go faster." In such circumstances Mr Mountain advises drivers "if at all possible to get out the way" so they don't feel pressured by the tailgater to exceed the speed limit and "compromise their safety".

Drivers who bunch up in congested traffic can also find themselves unintentionally tailgating but potentially involved in a pile up, Mr Mountain said.

A driver needs to allow sufficient distance to allow for reacting to a situation and sufficient braking distance

SA Traffic Support Branch officer-in-charge Superintendent Bob Fauser warned tailgating decreases a driver's ability "to see the road ahead and react in the event of the need to brake suddenly".

"A driver needs to allow sufficient distance to allow for reacting to a situation and sufficient braking distance," he said.

Supt Fauser said drivers should use the "three-second rule" to measure a safe distance from the vehicle in front.

"Choose a fixed point aligned with the car in front of you and ensure a three-second gap between your vehicle and the one in front as you pass the fixed point," he said.

But the decision of what is a "safe distance" between vehicles is up to the police, based on varying factors.

"These include weather conditions, general visibility, road conditions, speed and type of vehicle which all affect braking distances," Supt Fauser said.

Almost 90 per cent of rear-end crashes occurred in the metro area

"A police officer is required to estimate from their observations whether the rear vehicle is travelling too close and if necessary justify the estimations in court." Police crash data shows 31 per cent of reported prangs causing more than $3000 damage or injury involved a rear-end collision.

The crash data also shows that almost 90 per cent of rear-end crashes occurred in the metro area, and just over half occurred at intersections.