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[Auto Addict]

Collision Speeds

(Figures From The Thames Valley Police Accident Investigation Team)

Vehicle “A” is travelling at 30mph in a built up area, a child steps into the road and the driver manages to stop just before hitting him.
Vehicle “B” is travelling at 32mph, in exactly the same situation the vehicle will hit that child at 11mph.
At 40mph - 26mph
At 50mph - 40mph

Vehicle “A” is now travelling at 40mph on a road of that speed limit, a vehicle pulls out of a junction and the driver just manages to stop before hitting it.
Vehicle ”B” is travelling at 60mph, in exactly the same situation, he will hit that vehicle travelling at 45mph.

Vehicle “A” is now travelling on a Motorway at 70mph, for no apparent reason the traffic is stationary ahead of him, he just manages to stop before ploughing into the back of the vehicle ahead.
Vehicle “B” is travelling at 80mph, in exactly the same situation he will hit the vehicle ahead at 38mph.
At 90mph - 57mph
At 100mph - 71mph

Is this starting to build a picture? At the higher speed in each situation vehicle “B” is colliding at a speed greater than the maximum limit he should be driving at.

Makes you think doesn’t it?

[kris9128]

well thats just opened my eyes a bit. shows speeding just aint worth it.

[Plomien]

I am getting in the A car they have better brakes  
seriously though it does make you think

[jereboam]

"Vehicle “A” is now travelling on a Motorway at 70mph, for no apparent reason the traffic is stationary ahead of him, he just manages to stop before ploughing into the back of the vehicle ahead."

I'm not endorsing speeding, but if Driver A "only just manages to stop", regardless of the speed limit, he was driving too fast for the conditions.

[Auto Addict]

"Vehicle “A” is now travelling on a Motorway at 70mph, for no apparent reason the traffic is stationary ahead of him, he just manages to stop before ploughing into the back of the vehicle ahead."

I'm not endorsing speeding, but if Driver A "only just manages to stop", regardless of the speed limit, he was driving too fast for the conditions.

...but at least he stopped.....

[Entwood]

"Vehicle “A” is now travelling on a Motorway at 70mph, for no apparent reason the traffic is stationary ahead of him, he just manages to stop before ploughing into the back of the vehicle ahead."

I'm not endorsing speeding, but if Driver A "only just manages to stop", regardless of the speed limit, he was driving too fast for the conditions.

Missing the point somewhat I believe...  

[Jimbob]

Statistics can prove anything....

If you lie with your head in the freezer, and your feet in the oven....
On average you will be pretty comfortable  

[Auto Addict]

Statistics can prove anything....

If you lie with your head in the freezer, and your feet in the oven....
On average you will be pretty comfortable  

Try it the other way round then

But I think you'll find these are facts.....

[jereboam]

"Vehicle “A” is now travelling on a Motorway at 70mph, for no apparent reason the traffic is stationary ahead of him, he just manages to stop before ploughing into the back of the vehicle ahead."

I'm not endorsing speeding, but if Driver A "only just manages to stop", regardless of the speed limit, he was driving too fast for the conditions.

Missing the point somewhat I believe...  

I'm not missing the point - I fully understand the difference between colliding with a stationary object and not colliding with it.  Not colliding with it is usually the better option.  Adjusting speed to avoid collisions works quite well.

And if Driver A "only just manages to stop", there's a good chance that some buffoon behind him won't, with the result that he hits the car in front at whatever speed results from the second collision.

These are good statistics, but not in themselves a valid reason for blindly obeying speed limits.  Driving at 70mph on a motorway doesn't absolve you from blame if there is a collision.  Especially if the conditions indicate that a more sensible speed would have been 50mph.

[kris9128]

is it true that braking/stopping distances are still based on old cars or have they now been re-calculated to allow for newer cars with better braking systems ( abs, discs etc etc ) just curious

[Kevin Wood]

I think the example nicely illustrates the newtonian aspect of braking.

E=1/2mv²

Assuming a constant braking force distance is proportional to speed squared!

In practice both drivers were being reckless. Driver "A" would have got some nasty surprises  if it were raining, there were a pot hole in his braking area (not on our wonderful roads - a purely hypothetical situation!) or his reaction time was a few milliseconds longer.

In fact, due the the fact the so much of his speed clearly disappeared within the last metres of braking I wouldn't vouch for the condition of his underwear!

Kevin


Kevin

[Kevin Wood]

Damn! That echo's back.

[Kevin Wood]

is it true that braking/stopping distances are still based on old cars or have they now been re-calculated to allow for newer cars with better braking systems ( abs, discs etc etc ) just curious

I keep meaning to try some real stopping distances using my AP22 datalogger - on my private test track, of course.

Kevin

[Marks DTM Calib]

Yes, a classic example of how statistics can create a picture.

Consider if the person traveling at 30mph had braked 1 second later due to being on a mobile......

[jereboam]

Yes, a classic example of how statistics can create a picture.

Consider if the person traveling at 30mph had braked 1 second later due to being on a mobile......

Absolutely!  I'm afraid I was jumping ahead a bit.  These are excellent statistics, and they make me think - they should make everybody think.

But I can't read anything like that without automatically seeing the words "Speed Kills" appearing next.  

Stupidity kills.  Carelessness kills.  Speed turns an injury to a fatality, or a bad scare to an injury.  Driving too fast for the conditions is either careless or stupid.

Rant over