Mobile road block - Alwyn
Following our annual dinner dance, I was driving through Chester this morning at 02.00 hrs with a happily drunken passenger and his wife the back. He was amazed that I had been drinking water all night.

"Wouldn't it be great if the police stopped you" he slurred, "You haven't touched a drop not even a half of lager". Hmmm: not so sure I wanted to be stopped sober or not.

What I was very conscious of was, by sticking rigidly to speed limits, I honestly felt as if I was a danger and a pest to other drivers.

As we left the city centre and entered the outskirts, it was clear that 30 mph was needlessly slow and traffic was building behind me. Some of them of course overtook and continued on at a perfectly safe speed, probably around 40 mph.

By becoming a mobile roadblock, for no safety reason at all, I had caused/invited/ frustrated them into making an overtaking manouvre.

I now understand even more what highways engineers mean when they say that the safest speed of travel is the 85th percentile speed.

Sticking to limits in all circumstances, either faster or slower, can be very dangerous.
Re: Mobile road block - markymarkn
can someone explain the 85th percentile thing to me please?
Re: Mobile road block - Dwight Van-Driver
MM

It is the speed, that left to their own devices, 85 per cent of drivers would travel at on that particular stretch of road.

DVD
Re: Mobile road block - T lucas
Surely the point is to get people to slow down,how many times do you see people driving too fast and are not capable of controlling their vehicle,35 in a 30 can often be a very dangerous speed for somebody thats not concentrating and probably not aware that they have exceeded 30MPH.Lower speeds are going to come and i for one think its a good thing because there are too many low standard drivers on our streets.I really struggle to understand why Government allows car makers to sell cars with top speeds well in excess of 70MPH,whats the point of a Mondeo with a top speed in excess of 115 MPH?
Re: Mobile road block - ian (cape town)
TL,
Show me one new car available that will NOT do 70mph plus (oops, sorry Ladas are Slow)...
remember, a car with a top-end of 115 has the ability to accelerate at lower speeds much better than one with an 85mph top end.
I prefer having a powerful car, as it can get me OUT of trouble as easily as it can get me into it!
Having a car with a a bit of "poke" means you don't have to thrash it to get past somebody when you overtaking, for example. That said, I don't even know the true top-end of my car, as I don't feel safe in my own abilities above a certain speed, and our roads are notorious for the unexpected ...
It is only those with a small ego problem who have to rev the bejesus out of their engines and do silly things, like driving at inappropriate speeds, or becoming incapable with dealing with any particular happenstance which may come their way.
Re: Mobile road block - Alwyn
Simply slowing drivers down has been shown time and time again not to reduce fatalities.

Ask the folks of Suffolk. Suffolk police announced a crack-down on speed limit offences last January. Result?

Last year fatalities were 56. So far this year they have seen 102.

Same thing in Lincs. which has seen a 16% increase and Essex 29%.

When will they tell the truth?
Re: Mobile road block - Kevin

T lucas wrote:
>
> Surely the point is to get people to slow down,how many times
> do you see people driving too fast and are not capable of
> controlling their vehicle,35 in a 30 can often be a very
> dangerous speed for somebody thats not concentrating and
> probably not aware that they have exceeded 30MPH.Lower speeds
> are going to come and i for one think its a good thing
> because there are too many low standard drivers on our
> streets.

Jeez, how about fixing the problem and not the symptoms ?

> I really struggle to understand why Government allows
> car makers to sell cars with top speeds well in excess of
> 70MPH,whats the point of a Mondeo with a top speed in excess
> of 115 MPH?

I can see why you struggle.

OK, see if you can answer this one.....

Which car will stop quicker and safer from any given speed, a Nissan Micra or a Porsche 911 ?

Need a clue ?
Re: Mobile road block - Dave
Kevin wrote:

> Which car will stop quicker and safer from any given speed, a
> Nissan Micra or a Porsche 911 ?

According to the highway code they both stop in the same distance.
Re: Mobile road block - Alwyn
Tests by the wonderful Top Gear programme showed vastly different braking distances for different vehicles but all were shorter than the Highway Code distance which appear to have been done with Morris Marina's with drum braked that fade on the slightest hill.
Re: Mobile road block - Ben Chapman
Even my friends 1968 Morris Minor can beat the stopping distances given in the highway code.
Here is a question for you guys. If two identical cars are travelling along a road, one doing 70mph, and one 100mph, and they both stop as qucikly as they can (ie at the same rate), what speed will the faster car be doing when the other stops?

Ben
Re: Mobile road block - Mark (Brazil)
and how far away from the stopped car will it be, both at that point and when it finally stops itself.
Re: Mobile road block - Kev
Or, will a 911 stop from 100mph in less than the distance a Minor can from 70?
Didnt think they could get to 70 anyway!

Kev
Re: Mobile road block - Andy
Mr Lucas - The blanket lowering of speed limits is no answer to the inadequacies of a few drivers. That's like banning spoons 'cos some people use them for drug abuse.
If a driver is no good or behaves in a stupid manner, he should be dealt with and re-tested. This obsession with speed is naive and counter-productive, as Alwyn's post (above) and lots of other reports have proven.
Re: Mobile road block - careful driver
andy you are so right

why dont you stand for parliament ?
Re: Mobile road block - Andy
'Cos I'm not thick enough.
Re: Mobile road block - Brian
T Lucas
I do not believe that lower limits are the answer because each time you lower the limit you reduce the overall standard of skill.
Most drivers today have lived with the 70 mph upper limit. Many other drivers live in inner cities and rarely exceed 30 mph (well 40 if we are honest).
Driving at higher and lower speeds takes practice. A habitual inner city driver switching onto a motorway needs to adjust driving technique and thought processes, and vice versa, a long distance high speed driver needs to adjust to city driving.
The logical conclusion to your argument is that we progressively reduce speed limits to that which 100% of drivers can cope with (10 mph?), rather than improving driver skills so that they can cope with all circumstances.
Having said that, a driver who cannot cope with the range should not be on the road, or only with an experienced driver as a "co-pilot". Maybe the present driving test should be followed up by an extended test a couple of years later, failure of which would revert the subject to provisional status.
Re: Mobile road block - Kev
I agree with the last 3 people. In an ideal world we would not need speed limits. People would have the ability to decide what a safe speed is.

Lowering the limit to the lowest denominator is also not the answer. We should be raising people to the highest denominator.

Also, why shouldn't cars have a top speed over 70mph? I have been driven perfectly safely at 100mph and never passed a car. Is this unsafe?

Nice analogy about the spoons andy, I think. An object is rarely dangerous untill a human touches it. Cocaine is perfectly safe sat in a bag on a table.

Maybe we should spend the vast ammount of money being spent on traffic retarding on something that actually reduces acidents.

Kev
Re: Mobile road block - Brian
Agreed Kev
If the driving test is incapable of establishing that someone is safe to be let loose on the roads, then it is the standard of the test and subsequent enforcement that needs changing.

Practically everybody who is taught to drive passes the test eventually. Therefore we have 30 million licensed drivers out of a population of just under 60 million, one third of whom are too young or old to have a licence anyway.
Which means that practically every citizen between 17 and 70 who wants one has one.

Air travel is safer than road travel. Pilot training is more rigorous (and more expensive) than driver training, and pilots are subject to regular medical checks. A smaller proportion of the population is capable of being trained as a pilot. Maybe driving standards need to be moved in that direction.
Re: Mobile road block - Brian
Or the other way to look at it is that if, as a pilot, you make a mistake you have an odds on chance of killing yourself.
If you make a mistake as a driver you have an odds on chance of killing somebody else.
Good argument for no seat belts or airbags for drivers and the introduction of a pointed object in the middle of the steering wheel !
Re: Mobile road block - T lucas
My point is/was that like it or not speed limits are going to progresivly get lower and more plod/cameras etc to enforce them.Now we may think that we are very skillfull & safe in any condition drivers but there are a hell of a lot that are not and have no clue of what is going on around them so maybe driver training and testing should be ongoing.My 60 year old mother will often drive her 2.2 Camry at 85+MPH on the motorway,not a safe speed given her eyesite,reactions and concentration levels,but worse still is when she drives at 35+MPH in a 30 with the same reaction times etc.Unfair to pick on my mum but she is not the only one with that level of driving skills.Still no one has explained why mundane ordinary cars have to be capable of such high speeds over 70 MPH,maybe to help in the pub talk Grand Prix?
Re: Mobile road block - Andy
TL - would these '30 limits' that your mother so blatantly exceeds be on roads that used to have 40 or even 50 limits? Perhaps she is simply driving at the most efficient speed for the road - the 85th percentile. Perhaps she bases this on years of safe driving.
Lots of roads around here -wide ones with wide grass verges- have been attacked with paint and '30' signs recently, despite the roads being perfectly safe at 40 or fifty (and until recently were posted as such).
If you read through the posts you will see that most of us aren't irresponsible petrol-heads who want to 'drive when we like, where we like and as fast as we like', indeed we would be happy to see 30 signs and cameras in accident hot-spots and around schools, but we get cheesed off when we are limited to 30 on roads that are clearly safe at higher speeds.
Re: Mobile road block - T lucas
I think school areas should be 10/15 MPH and enforced at in/out time US style.if you want to witness bad,dangeous driving come to my sons school at in/out time,un****ing believeable.
Re: Mobile road block - Andy
I'd agree with the point about the school run. Around here, the parents (especially the females!) seem to have no idea.
They don't park, they just abandon their cars wherever they can, flinging the doors open and getting their kids out on the road side of the car.
Then they pull away without any indication. It is these idiots that make the school drop-off dangerous, not the people who are trying to drive by and get to work....
Re: Mobile road block - Kev
You may have missed it but I gave a perfectly reasonable explaination as to why cars can do more than 70mph, and that is because it is often safe to do more than 70mph. Please note safe.
I agree with your ideas about outside schools, it should be slow, 10-15mph sounds about right. But would this be 24/7, or just at turning out time? What about during school holidays?
These are all important things to consider, but me thinks the council/government won't. They will just stick a blanket 15mph speed limit anywhere near schools, which will be enforced by a forest of speed cameras all dy and all night. Watch this space.
Then like weeds the zones will expand and expand to cover the whole village. And people will be amazed that children are still being hit by cars [albeit at a slower rate, but a broken arm/leg is still a broken arm/leg] untill they realise that its the children who are the cause of accidents by running infront of cars rather than cars mounting the pavement and hitting the innocent children [vandalising a bus stop, ;-)]

Lowering speed limits will help, but untill pressure groups realise that it may not just be the car drivers fault, there will always be accidents.

Kev
Re: Mobile road block - Brian
On the way home tonight there was what looked like a normal young lady, probably around 20 years old, who was crossing the road on foot at traffic lights after the lights had changed against her.
I missed her, but she was one third way across the road on a one way street with two more lanes to cross.
Whether she succeeded in committing suicide, whether she caused an accident but escaped herself or whether everybody else missed her without pranging another vehicle, I do not know, but as an exercise in sheer idiocy it took some beating.
Re: Mobile road block - Mark (Brazil)
Brian wrote:
> but as an exercise in sheer idiocy it took some beating.

I used to work on the Science Park in Cambridge and live in Lode. This entailed a 10 minute drive on the extremely fast and busy A14 with a brief small road at either end.

Some years ago, I'd guess 89 or thereabouts, I drove home one evening jsut to get my jeans on before going out.

As I was pulling off the A14 at Lode, a jacket came flying out of a car a few in front of me, followed by the women driving the car pulling over onto what passes for a shoulder there.

In my rea-view mirror I saw her standing there contemplating running out into the middle after her jacket.

About 15 minutes later I drove back past in time to see an ambulance arrive to take her body away, it having been stomped by a truck.

All for a jacket.
Re: Mobile road block - Andy
There's a junction near here where pedestrians stand in the middle of the road, waiting to cross. There is no central refuge and cars whiz about on all sides. Just 20 yards along the road is a light-controlled crossing. Then we drivers get the blame.....
Our shopping street is 300yds long and now spoerts FOUR crossings, two of them recently narrowed. But pedestrians still hurl themselves into the path of oncoming vehicles, or worse still, slowly shuffle out into the road so drivers have to swerve. And it's all our fault.....
Re: Mobile road block - Brian
30 mph and 66 feet ?
Re: Mobile road block - Dave
Brian wrote:
>
> 30 mph and 66 feet ?


Nah, it'll be exponential won't it...
Re: Mobile road block - markymarkn
If i remember rightly...

Assuming constant acceleration,

s=ut + 0.5at^2

v^2 = U^2 + 2as

s=distance, (m)
u=initial velocity (m/s)
t=time (s)
a=acceleration (m/s^2)

Plug the numbers in, should give you a rough estimate. Does anybody know roughly the rate of decelleration of the average car?
Re: Mobile road block - Stuart B
"Does anybody know roughly the rate of decelleration of the average car?"

Mark,
I am willing to be corrected here but I think that to pass an MOT test the service brake has to be 50% efficient which I have always took to mean can produce a decelleration of at least 0.5g. I think if you can achieve 1.0g then that is very good for an average car though some can better this a little
.
Might I suggest you plug in a range of figures between 0.5g and 1 g where g is 9.8 m/s^2
Re: Mobile road block - Brian
Having though about it, I think my estimate of 66 ft is probably wrong and you cannot get the distance answer without knowing the rate of deceleration, so Martin (Brazil)'s question was a trick.

Or, in computer terms, "Insufficient data: Cannot compute"
Re: Mobile road block - Brian
I must be showing my age, I still use 32 ft per second squared !
Actually that's easier when also using mph, where 60 mph = 88 ft/sec
 

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