Two Seconds Rule

97% of all road accicents are caused by driver error - following too close is one of the errors most often cited.

 

So what's all this stuff about the 'two second rule'?

At 30 miles an hour, a car travels 88 feet (26.83 metres) in two seconds.

A fit, alert and attentive human being, concentrating on the road ahead and the traffic around them would have a reaction time of at least 0.6 second. This means, if the brake lights of the car in front come on, it takes 0.6 second for your eyes to tell your brain to apply the foot brake, and for your foot to start lifting off the accelerator. Next, your foot has to travel from the accelerator and across to the brake pedal, before you can apply pressure and slow the car.
At 30 mph, you are already nearly 30 feet (9 metres) closer to the car in front.

Once you've applied pressure to the foot brake and the brake pads start to bite against the discs the car will begin to slow down and eventually stop. When it does it will have travelled another 46 feet (14 metres).

The above figures are the best case scenario. If your car's brakes are poorly maintained, or tyres not in tip-top condition, or the road surface is wet or greasy, the distances mentioned above will be greater; much greater.

So, if you are travelling two seconds behind, you should have a pretty good chance of not running into the back of the car in front.

How do I know when I am two seconds behind?

Pick a mark on the road, say a bridge's shadow, or manhole cover. As the car in front crosses the shadow, say to yourself, "Only a fool, breaks the two second rule." This should take you about two seconds. If you cross the same mark before you have completed the sentence, you are too close. Aim to be far enough behind to complete the sentence before you reach the mark. Easy.


But what if I am travelling faster than 30, will the two second rule still work?

Yes, it is a useful guide. The faster you go, the greater distance is covered in two seconds; 176 feet (54 metres) at 60 mph. But, the Highway Code suggests that stopping distances get proportionately longer - 240 feet, 73 metres - so, speak more slowly.

When you are next on the motorway, check to see if you are complying with the Two Seconds Rule, and if not ... Back Off!

Just for fun you can test your reaction time here:

http://www.mathsisfun.com/games/reaction-time.html

... and check out stopping distances here:

http://www.passingplacedriving.co.uk/stoppingdistances.html