Following Distances


An article by Eddie Wren — © Copyright 2004-2005


Exactly how far should you be, behind the vehicle ahead, so that you can still stop safely if that other vehicle has a tire blow out or if it hits an obstruction? You can drive for years or even decades without such a crisis happening, but if ever it does and you are too close….!

Many years ago, the advice was that Only a Fool Breaks the Two-Second Rule…….(but now there’s more to it than that!)

For decades, people who claim to be expert drivers have recommended that at certain speeds you should drive so many car lengths behind the vehicle in front, but this raises two serious problems:

Firstly, nobody says what size imaginary car we are meant to be using to gauge the gap (for example, a Mini, or a GMC Yukon SUV — there can be a huge difference in car’s lengths).

Secondly, very few people indeed are capable of accurately judging car lengths from their own position in that line of imaginary cars. And if it’s not accurate, it’s probably not safe.

But this problem is easily solved. Simply watch the vehicle that is ahead of you and as it passes a fixed object (never a moving one) start to count: “One-thousand-one, one-thousand-two, one-thousand-three…” etc. (Good examples of suitable ‘fixed points’ are bridges, electricity poles, painted markings on the road, manhole covers, etc., but many other objects can be used.)

Nowadays, the updated rule must read:

Only a fool breaks the 2-second, 4-second, 10-second rule!

If you are on a dry, clear road and you reach the same fixed point before you have said the ‘two’ then you are too close and need to drop further back, to create the essential minimum of a two-second gap. And if you prefer three seconds, rather than two, that’s okay.

If you are on a wet road then you need to have at least a four-second gap.

And if it’s icy or you are driving on compacted snow or somewhere you know that something slippery (such as diesel fuel) has been spilled, then it is wise to create at least a ten-second gap, so you would need to count all the way up to ‘one-thousand-ten’ before you reach the same fixed point that you watched the vehicle ahead pass. Yes, it will look like a huge gap, but who cares? Your life, or even your car merely being damaged, are worth more than the opinions of those who don’t understand your own greater knowledge of safety. For information on driving in winter conditions, click here.



Some people will tell you that the minimum gap should always be three seconds, not two, but unless these people go on to explain that you would need to extend this time by margins similar to those above, whenever the road is wet or slippery, they are probably just telling you something they read in a book or heard somewhere. You need to get your information from more knowledgeable sources.

There is nothing wrong with a three-second gap on dry roads but as soon as the surface gets wet, or even just damp, three seconds becomes inadequate.

Sadly, because almost everybody drives, almost everybody considers themselves to be an expert on the subject of driving — but nothing could be further from the truth.  Think about it.  Many of the people who value their own “expert” knowledge have never done any training other than learning to pass a remarkably basic driving test, and have never taken any higher level examinations on either their own driving skills or on their in-depth knowledge of road safety issues, either.

We would suggest that this is like somebody telling you that they are an expert nutritionist just because they eat, or a world-class sprinter just because they have legs.

The truth is that expertise in any of these fields requires serious, long-term training and none of them can be learned to a truly high level by the self-taught. Yet few other subjects, when done wrongly even for just a split-second, can be as deadly as driving.



Lastly, if an impatient driver passes you — as they often will — then restart your checks on their vehicle and drop back once more. It may test your patience, but it’s better to test your patience than to test the resilience of your skull, as your car slams into the vehicle ahead because you were simply driving too close and couldn’t stop.

The only excuse, ever, for hitting the vehicle ahead is that your own car was firstly hit from behind by someone else, and you were then knocked into the one in front. “Ice on the road” is not an excuse: that simply means you weren’t paying enough attention to the weather or the road surface conditions and either you didn’t leave a big enough gap between the vehicles or you were driving too fast for those conditions. “The driver ahead stopped suddenly” doesn’t cut it, either. Your job is to be prepared for these things. If ever you are not ready then you are driving badly — period.  Harsh words? Yes — sorry — but simple facts, none-the-less.

Click here for Stopping Distances

If you wish to view the background and credentials of the writer of this article, click here.