RE: Stopping Ignorance
Tuesday 23rd September 2003
Stopping Ignorance
Is it important to know the recommended stopping distance at 30mph? How relavent is it?
Discussion
What they don't say is, if you're already covering the brakes then the braking distance is only 12 meters, if you're caught by surprise (and have normal reactions) this doubles, if you're yacking on the phone and gawping at the shop windows you probably won't see the hazard until after you hit it. So what makes more difference - speed, or paying attention? 
>>> Edited by GreenV8S on Tuesday 23 September 13:29
>>> Edited by GreenV8S on Tuesday 23 September 13:29
I dont think it matters if you know the distances because it is difficult to translate 20 or 50 or 100 metres into what you see on the road.
It would be better if you learnt what 20 or 50 or 100 metres looked like when travelling at various speeds so that you could maintain those distances.
It would be better if you learnt what 20 or 50 or 100 metres looked like when travelling at various speeds so that you could maintain those distances.
I'm a bit worried that if everyone DID know the stopping distance AND could measure it accurately while driving, it would lead to people driving according to the "rules" rather than driving safely. It's the same mentality that says "70mph is safe and 80mph is dangerous". Other than under strictly controled test track conditions, I never seem to be able to get the same car to stop in the same distance twice! There are LOADS of factors governing how well a vehicle can stop and the numbers in the back of the highway code are a gross over-simplification. My vote would be to make people aware of the "average" distance (give or take half a dozen car lengths) but to emphasise the large variation one might encounter. Incidentally, for tests I have been involved in, a good sportscar with modern road tyres on dry tarmac can nearly HALVE these distances!
See, now you're going to start letting people making "judgements" and that's just plain dangerous.
What we need is a braking distance camera to catch all those too close/too far from the car in front the world would be a better place . The rules would be followed and no-one would have to think for themselves!
What we need is a braking distance camera to catch all those too close/too far from the car in front the world would be a better place . The rules would be followed and no-one would have to think for themselves!
23 metres is a long way to stop from just 30mph.
I'm positive my car (Fiesta Zetec-S) stops way less than that. Probably more like the 12 metres/3 car lengths as mentioned in the article.
A TVR or Evo VIII or 911 with big powerful brakes must surely be even better.
The highway code needs to be updated.
I'm positive my car (Fiesta Zetec-S) stops way less than that. Probably more like the 12 metres/3 car lengths as mentioned in the article.
A TVR or Evo VIII or 911 with big powerful brakes must surely be even better.
The highway code needs to be updated.
ditto...and additionally I couldnt indicate an object that was 23 metres away accurately! I know my father and other keen golfers are excellent at judging things like this...but personally I know I can't.... that said, I know EXACTLY what that equates to in my various cars when actually driving them....
Using the braking data from the Autocar 0-100-0 tests and assuming constant decelleration (and that my maths/physics are correct ) it shows that most cars they tested would stop from 30mph in about 8 metres (the worst required 11 metres). This excludes reaction time.
Now clearly Joe Numpty doesn't always drive around in such exotica, but its still a long way from being a 23m stopping distance.
Oh, and for the record the best (a Caterham R500) would stop in 7.4m.
) it shows that most cars they tested would stop from 30mph in about 8 metres (the worst required 11 metres). This excludes reaction time. Now clearly Joe Numpty doesn't always drive around in such exotica, but its still a long way from being a 23m stopping distance.
Oh, and for the record the best (a Caterham R500) would stop in 7.4m.
I also don't know the distance and as has already been stated I couldn't relate that to anything whilst driving.
What is useful is to actually try an emergency stop from 30-60mph, particularly on a wet surface. It can be surprising how long it takes to stop.....
Once you have experience this I think you leave a greater gap to the car in front.......
What is useful is to actually try an emergency stop from 30-60mph, particularly on a wet surface. It can be surprising how long it takes to stop.....
Once you have experience this I think you leave a greater gap to the car in front.......
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