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 blowout or if it hits an obstruction? Of course, you can drive for years or even decades without such a crisis happening, but if ever it does, 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 use to gauge the gap (for example, a Mini or a GMC Yukon SUV — there can be a huge difference in car lengths).

Secondly, very few people can accurately judge car lengths from their position in that line of imaginary cars. And if it’s not accurate, it’s probably not safe.

But this problem is easily solved. First, 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, maintenance hole 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 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, you need 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 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 more excellent 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. Still, 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. Therefore, you need to get your information from more knowledgeable sources.

Nothing is wrong with a three-second gap on dry roads, but three seconds become inadequate as soon as the surface gets wet.

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 people who value their “expert” knowledge have never done training other than learning to pass an actual driving test. They have never taken higher-level examinations on their driving skills or in-depth understanding of road safety issues.

We would suggest that this is like somebody telling you 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 severe and long-term training, and none of them can be learned to a genuinely high level by the self-taught. Yet few other subjects, when done wrongly, even for 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 again. 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 are driving too close and can’t stop.

The only excuse for hitting the vehicle ahead is that your car was first 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 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 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, you are driving badly. Harsh words? Yes — sorry — but simple facts, nonetheless.

Click here for Stopping Distances.

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