Speeding in a thirty limit

[Deleted member 15344]

That is my point - there are many variables in the real world which is why I simply will not accept that there is 1 figure for a stopping distance for a car doing speed A. Quite simply, it depends...

I don't think anyone has said there is only one stopping distance but I'm not sure of the relevance right now

Some cars will stop quicker but some will stop slower

But it shouldn't effect the speed you are doing within certain areas

 

[Foxholer]

Foxy, they're not my figures, they're the SDT figures. If you're that hung up on them Google them. One thing this exercise has shown is that there are a number of sources that quote different figures for survival rates but the figures that are diffinitive is the significant reduction in fatalities where 30's have been changed to 20's. BTW Foxy, they're your figures.

Nope! You quoted them; Your responsibility to provide the reference/link! Otherwise the B/S call stands. And I still think it's B/S (or other 'error') anyway, because so many other sets of figures have been close, but not the same, as the ones in the link I posted.

 

[Deleted member 15344]

More people die getting hit by a car at 30mph than 20mph - the risk is greater at 30mph

The exact figures shouldnt make a blind bit of difference

If people are far more likely to survive getting hit by a car doing 20mph then it makes sense to reduce the speed limit to that from 30mph

Unless of course you want to drive around estates at 30mph

I most certainly don't want to see 30mph in residential areas

 

[Blue in Munich]

Of course, but that same car at 30 may be perfectly capable of stopping in a shorter distance than another car doing 20.

There is a minimum distance in which any vehicle can stop from any speed on a given road because it is governed by the laws of physics. And carbon ceramic brakes will not reduce that any further, so no, if maximum braking effort is applied in both vehicles it is not possible, assuming that both vehicle's braking systems are properly maintained and working correctly.

I don't think anyone has said there is only one stopping distance but I'm not sure of the relevance right now

Some cars will stop quicker but some will stop slower

But it shouldn't effect the speed you are doing within certain areas

They will, but the difference between them is minimal and not as much as some people would have you believe.

 

[Deleted member 15344]

There is a minimum distance in which any vehicle can stop from any speed on a given road because it is governed by the laws of physics. And carbon ceramic brakes will not reduce that any further, so no, if maximum braking effort is applied in both vehicles it is not possible, assuming that both vehicle's braking systems are properly maintained and working correctly.



They will, but the difference between them is minimal and not as much as some people would have you believe.

I agree the difference is prob minimal

 

[ger147]

There is a minimum distance in which any vehicle can stop from any speed on a given road because it is governed by the laws of physics. And carbon ceramic brakes will not reduce that any further, so no, if maximum braking effort is applied in both vehicles it is not possible, assuming that both vehicle's braking systems are properly maintained and working correctly.



They will, but the difference between them is minimal and not as much as some people would have you believe.

More assumptions...

 

[Doon frae Troon]

I am all for 20mph limits in residential areas but it does need to show a bit of common sense.

In our village we have a newish development of about 15 houses that have their own wee 20mph signs. The road that these signs cover must be all of 40 yards long. Perhaps the cooncil thought that the residents would all be Ferrarri drivers.

 

[Foxholer]

If people are far more likely to survive getting hit by a car doing 20mph then it makes sense to reduce the speed limit to that from 30mph

Wrong! It may makes sense to reduce the speed of vehicles (in certain areas) from 30mph to 20mph, but that is not the same thing!

I most certainly don't want to see 30mph in residential areas

That depends on the nature of the road. Plenty of areas where 30 or even maybe 40, is fine imo!

 

[Andy808]

The theory is that there is a 10% leway for mechanical differences in the speedo but the speed limit is 30 so you can be done for anything over 30.

 

[SwingsitlikeHogan]

This is most strange, I find myself agreeing with Phil!!

I always relate speeding to cheating, so don't start greeting when you are caught and have to pay the penalty.
Lack of knowledge of the rules is no excuse in the law.

Me too - just read the post of LPs you commented upon and I was thinking exactly the same - I agree with Phil

 

[Deleted member 15344]

Wrong! It may makes sense to reduce the speed of vehicles (in certain areas) from 30mph to 20mph, but that is not the same thing!



That depends on the nature of the road. Plenty of areas where 30 or even maybe 40, is fine imo!

So how do you reduce the speed of vehicles down from 30 to 20mph without decreasing the speed limit ?

And please stop telling people they are wrong in the way you are - it's very abrasive and not always strictly true

 

[London mike 61]

No one should be surprised if they get done for speeding, or driving whilst having a mobile stuck to their ear. Both illegal and both dangerous. We may not like them but thems the rules.

 

[CheltenhamHacker]

More people die getting hit by a car at 30mph than 20mph - the risk is greater at 30mph

Phil, have you a report that shows this? Everytime I made a common sense statement as above in the m40 thread, you asked for supporting evidence also, you can't extrapolate the "risk" from that statement. Just because more people die, doesn't mean a higher risk.

 

[Deleted member 15344]

Phil, have you a report that shows this? Everytime I made a common sense statement as above in the m40 thread, you asked for supporting evidence also, you can't extrapolate the "risk" from that statement. Just because more people die, doesn't mean a higher risk.

Not all motorists will like it but the research underlines work by the Department for Transport in 1999, which showed that reducing traffic speed to 20mph led to a 50 per cent drop in the number of six- to 11-year-olds killed or seriously injured. That’s partly due to the speed of impact, because pedestrians have a 90 per cent chance of surviving being hit by a car at under 20mph but a less than 50 per cent chance of surviving at 28mph or higher.

http://www.telegraph.co.uk/motoring/road-safety/8644983/Why-20mph-limits-help-save-lives.html

 

[CheltenhamHacker]

This doesn't say anything about the amount of people that die at 20mph and 30mph

 

[Deleted member 15344]

This doesn't say anything about the amount of people that die at 20mph and 30mph

As I said in the original post - the exact figures shouldn't make a blind bit of difference :thup:

 

[CheltenhamHacker]

As I said in the original post - the exact figures shouldn't make a blind bit of difference :thup:

Ah but it could well do! If very few people die at 30mph, then nothing will be saved by decreasing the limits in those areas.

Side note, that article actually says 20mph shouldn't be applied too much!

 

[Deleted member 15344]

It shouldn't be applied too much - should be used in the correct and appropiate areas

Housing estates , near schools , busy pedestrian areas.

 

[Foxholer]

So how do you reduce the speed of vehicles down from 30 to 20mph without decreasing the speed limit ?

Read the Factsheet that I linked to and you will see how

http://www.rospa.com/roadsafety/advice/highway/info/20-mph-zone-factsheet.pdf

It also provides the answers as to why you were wrong! I welcome any correction when I am wrong and am prepared to admit it when I am. The same doesn't seem to apply to you, though you are not unique!

And the chart on Page 1 provides the evidence CheltenhamHacker seems to be looking for - though, imo, it's pretty self evident in this case.

 

[Foxholer]

There is a minimum distance in which any vehicle can stop from any speed on a given road because it is governed by the laws of physics. And carbon ceramic brakes will not reduce that any further, so no, if maximum braking effort is applied in both vehicles it is not possible, assuming that both vehicle's braking systems are properly maintained and working correctly.

More assumptions...

Er. No! There's a formula. The fastest a moving car can reduce velocity (actually Kinetic Energy) to zero (minimum distance) is a function of the Friction between the Road and Tyres, the (square of the) Velocity and the Mass of the vehicle (that's the laws of physics that BiM is referring to). More efficient brakes/braking will mean any extra distance is minimised. Having a lower initial velocity is the best way to significantly reduce stopping distance.