Urban motorways are set to 50 based on the fact that they've got a large number of junctions, with short slip roads and can often have sight lines less than the stopping distance at 70MPH. They've often got narrower lanes.
Sub-urban have less twists and turns, less junctions, so can be 60.
There's a nice example in Glasgow city centre, eastbound at Charing Cross, where the sight line round the corner through a tunnel makes it unsafe to even take it at 50 never mind 70 - and yes I have come round that corner into stationary traffic, late at night (when most people would advocate driving even faster) due to off peak roadworks closing 3 out of 4 lanes.
I would say most people would think that speed limits should be higher until they actually have to stop in a real emergency, then if they're lucky they'll soon realise why speed limits are what they are for a reason.
I only wish a popular program like Top Gear would do a segment proving once and for all that despite what the majority of drivers think, the laws of kinetic energy do really apply to cars. As the famous engineer due to be born in Lithgae in about 214 years time will say "Ye canny break the laws of physics, captain".
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Don't be ridiculous, shawad. Everyone knows that a BMW 530i handles and brakes far better than 95% of other cars, the fact of which does indeed negate the laws of physics and means that it can be driven with "no danger" at over 100mph in a 60 limit.
You really should pay more attention to this forum.
;-)
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I have been commuting on the A583 in Lancs for many years
Originally it was a 70mph dual carriageway. Traffic was never a problem, I used to be able to make it in about 12 minutes.
They they changed it to 60mph, traffic increased and journey time increased slightly.
Next they reduced part of it to 50mph and journey time and traffic levels increased further.
Then they reduced all of it to 50mph, made 50% of the road single lane with a middle "suicide" overtaking lane.
Now it takes me 30-40minutes to make this particular 12 minute journey in the morning, and I spend far longer than I would like in the middle suicide lane trying to overtake tractors travelling at about 25mph.
So thats more frustrated drivers, more accidents, more speeding tickets, more fuel wasted, more pollution.....
And then there is all this talk of congestion charging ........ well put the bloom'in speed limits back to what they should be and reduce the congestion then, instead of decided (in addition to the speeding fines) that its a nice way to make some money.
I can't believe how backwards the UK is. We never progress do we? Speed limits were mostly set 30-40+ years ago where most cars would struggle to reach the speed limits. Instead of increasing them, we decrease them.
30mph limits are perfectly sensible for built up areas, but why do we keep having to reduce the speed limits on clear, wide open A roads.
All the 40mph roads in Blackpool have now been dropped to 30mph. Infact one road in Blackpool, that is a dual carriageway and was 40mph for all its life, was dropped to 30mph and then immediately speed cameras completly covered the road. For anyone who knows Preston New Road in Blackpool will know it has the most densley located speed cameras in the whole of the UK. At one point there are 3 in a row on the same side a few yards apart.
These days cars are faster and safer, and that is rewarded by making the roads slower and more congested.
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Eastern Road in Portsmouth has recently had part of it's dual carriageway section reduced from 70mph down to 50mph. Do you know what? I actually agree with this change. On the part that was 70mph, there were some sections where there was no crash barrier or separator in the middle, meaning two cars north/south bound in the outside lane had a possible 140mph+ closing speed with no protection. There have been several accidents along this road, so now there is a 50mph limit, with I believe crash barriers to be installed in the near future.
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They did that to a dual carriageway near here, and it was very similar to the EL, traffic lights, no slip roads, small roads joining all over the place, cars crossing the reservation at those junctions... and people travelling at well over 70... though I suspect that if people hadn't kept having fatal crashes I suspect they may have left it alone... your answer perhaps?
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If speed of an aeroplane falls below a certain limit, its wings can't generate enough lift to keep it airborne.
Unless you achieve enough speed in bicycle, its too difficult to keep balance (just try yourself).
So, every moving object has some optimum speed, below which its efficiency (or even purpose) reduces drastically.
Unfortunately, many people (including some law makers) do not understand this concept and assume that low speed is always better.
We often hear that if you go 10 mph faster, you'll only save 2 minutes on overall journey time.
Well, simple deduction doesn't work. On my morning commuting, I need to pass through nearly a dozen of traffic lights. Sometimes I manage to cross them barely before turning amber/red. So, each 1-2 mph more might allow me to cross a traffic light which otherwise would have increased my journey time much more than just 2 minutes! At rush hours, every minute counts.
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Of course they are arbitrary. The urban 30mph limit has been in force since cars' stopping distances were twice what they are now. And as for this progressive spoiling of urban and extra-urban dual carriageways with lower and lower limits and these ghastly cameras...
Of course today's traffic density is no joke. Even so the moronic idea that speed kills, with its half-witted corollary that slower is safer, is used by politicians of all sizes to make themselves more and more of a nuisance, one suspects in the main to maximize speed tax revenue.
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>>.... well put the bloom'inspeed limits back to what they should be and reduce the congestion
If you take into account braking distance, slower roads have higher traffic capacity. If you increase a speed limit you actually reduce the vehicle throughput of that road. I'm sure NC has the data to hand...
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I quite like the suggestion, can't remember its origin unfortunately, that the speed limit in motorway contraflows should actually increase to 140mph. End of contraflow induced congestion . No danger to workers 'cos there never are any.
;-)
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It might have been me HB. I have suggested here more than once that the speed limit should be doubled when there is a 2-into-1 lane closure to eliminate tailbacks.
It's only a utopian dream though. Someone would be sure to screw it up.
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