I was on a German autobahn with two bikes on the roof last summer. The main difference was that I had a choice between being overtaken at a frightening speed differential if I stuck to 80 mph, or hoping the bikes stayed put on the roof at 100 to reduce the gulf.
Neither option was particularly thrilling. I think I'd avoid it unless I was able to cruise at 120 next time. I believe it's even worse when trucks are on the road (I have a memory of there being none, but I could be mistaken, I was only on there for about 20 miles) when you can either do 56 or 120, but not really anything in between.
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What is the esential difference bewtween our Motorways and the German alternative??
Absolutely awesome degrees of engineering and extreme quality of manufacture & maintainence.
There was a programme on the Discovery Channel a wee while back about the Autobahns that was very, very good. To many things to repeat, but maximum rates of climb & maximum rates of curvature are two that I can instantly recall.
MTC
p.s. people who have been on the Autobahns rave about the level of lane discipline - nothing like the rhubarbs and custards in the Uk who refuse to use lane 1 for multiple reasons.
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"Absolutely awesome degrees of engineering and extreme quality of manufacture & maintainence."
Just like their cars then...
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p.s. people who have been on the Autobahns rave about the level of lane discipline - nothing like the rhubarbs and custards in the Uk who refuse to use lane 1 for multiple reasons.
Tosh! I have never been cut up so badly as I have been on German Autobahns.
Just because you are allowed to go faster does not mean it is always possible.
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I've seen some terrible driving on autobahns - and some terrible autobahns too.
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I've seen some terrible driving on autobahns - and some terrible autobahns too.
Don't blame the Cat !!
Blame the makers of the Discovery Channel article.
MTC
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I have always been impressed by the fact that drivers on the German autobahns are (usually) very aware of what is coming up behind them and take appropriate action in good time.
- - - - - - - - - - - - - - - - - - - - -
What\'s for you won\'t pass you by
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>>Absolutely awesome degrees of engineering and extreme quality of manufacture & maintainence.
There was a programme on the Discovery Channel a wee while back about the Autobahns that was very, very good. To many things to repeat, but maximum rates of climb & maximum rates of curvature are two that I can instantly recall.>>
Some autobahns are awful, badly rutted, terrible drainage, and many have 100, 120 or 130 kph limits the point is though that on those that are unrestricted you will get done for dangerous driving if going excessively fast in inapropriate conditions, i.e the wet, heavy traffic etc.
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If the Disco Channel ever repeats it, please try and watch it and pick up on the things that I did.
I seem to remember that the road surface was 4 times deeper than used on Uk motorways and was capapble of having 747's land on it (not that doing so was recommended) - but my memory may be palying tricks on me and it may have only been 3 times as deep and they may have been DC-10's
MTC
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...What is the esential difference bewtween our Motorways and the German alternative??.....
Better lane discipline.
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Not many unrestricted autobahns left-get there quick;having said that was on the A11 near Newmarket at the weekend,was doing between 80 and 85 mph.,was in the left lane and was being overtaken by absolutely everything!!
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When is the UK set for a 80mph limit??!
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If anything it'll get lowered.
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I thought they were going to raise it (to effectively 82mph?) if we went metric, to standardize across Europe.
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I can just remember the motorways before a speed limit was introduced. My father worked for a luxury car maker and so when he had one of their products for the weekend we used to ask him to do 100 mph on the M1. I can remeber being driven at an indicated (repeat indicated) 120 mph. At that time Midland Red was operating coaches at 80 mph, some of which were reputedly capable of 100 mph. Midland Red built these legendary coaches themselves, including the engines.
Then came the 70 mph limit.
So what is the difference between then and now? Simple - volumes of traffic. There is too much traffic on the motorways to raise the limit. We all, myself included, like to think that we'd be safe driving at 90-100mph but we forget that everyone else would be doing the same from boy racers to White Van Man!. People would become targets for road rage for hogging the centre lane at 85mph due to lane one being clogged by artics doing a controlled 56mph.
So how about raising the limity for a clear, empty motorway? The problem is defining a clear, empty motorway in law!
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So how about raising the limity for a clear, empty motorway? The problem is defining a clear, empty motorway in law!
Legally enforcable variable limit signage as per the M25, up to 90 on a clear day when you can see forever, down to 40 when it's raining, it,s pouring!
Another thing, yes volume of traffic is an issue however if the average speeds can be raised jurney times would lessen and there would be less vehicles on the motorway at any one time, an approx 10% increase in average speed would enable an approx 10% decrease in volume of traffic, significant.
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Only in the very clear bits where there's no excuse for reducing it still further.
Honestly I wonder why we bother.
A motorists' strike would be a thought were it not for the well-known reactionary voluntarism of that species...
imagine though three days of zero petrol sales and zero speeding fines. Might concentrate a few minds.
But it's cloud-cuckoo-land. If it came to a confrontation, they could outlast us. Pink fluffy dice (is this ok DD?)
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If you travel south from Kassel you will endure some of the worst bends and steepest hills on any motorways I have ever seen although there are some unrestricted stretches, the autobahns have very large amounts of varying speed restrictions and are well enforced
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Circa 1990 they imposed limits on some autobahns in the east of what was West Germany to avoid newly liberated Trabant drivers pulling out to overtake trucks with no perception of the speed of the S-Class etc that might be coming up behind at 200 kph +. Some restrictions were removed and some stayed IIRC.
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rubbish
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rubbish
Are you saying my post regarding post unification restrictions is rubbish? If so it is really nice to see some reasoned argument, well thought out rationale and presentation of facts to support you point! ;-)
No, seriously it is true, I did a lot of driving in Germany at the time, Hamburg to Lubeck was effected and the section up to Puttgarten IIRC as were one or two of the sections east of Hannover.
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A4,2,9,72 had various limits before 1989 and still had the same limits after 1989 as the roads were and are being refirbed various new limits are applied from 80k upto derestriction.At no time was any limit put on due to Trabants ,the eastern block trucks were far more dangerous having no safety checks of any kind you still see trabants around on the new roads but unlike uk drivers they know to look before they pull out.
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Circa 1990 they imposed limits...
I remember reading that most former-East German autobahnen had 100 km/h limits on them for 2 reasons, firstly because that's allegedly what a Trabant 601S could do flat out, and secondly because of the quite shocking state of the road surfaces, which in some cases had hardly been touched since before WW2, except to patch up bomb damage.
Do a Google on this and look for pictures of the A4, I think between Leipzig and Halle if memory serves - I recall reading that some parts of it became so disused that they closed it and built warehouses down the middle, and the road surface had axle-breaking potholes and patchwork repairs so bad that 20 mph was about the fastest you could go safely.
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A4 goes nowhere near Leipzig or Halle ,the road in question was always open it starts at Nossen and now ends at Magdeburg joining the 4 with the 2 it did end north of Halle it is still two lanes and has a limit of 120 km.There is a new three lane section by the new airport derestricted the section from Leipzig to Dresden is still under refurbishment and is and will be two lane but had sections derestricted before and after 1989.Having lived in the east since before 1989 I know of nowhere were buildings were put up on the roads .I will agree the condition of the roads was absolutly disgusting a bit like the UK now the best being cobbled slip roads and non existent bridges.
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A4 goes nowhere near Leipzig or Halle
Memory clearly didn't serve on this occasion. Sorry! :-)
I know of nowhere were buildings were put up on the roads
I've found the site where I read all this - go to www.autobahn-online.de/images/gallerie.html , scroll down to "Autobahnen in der ehemaligen DDR" and have a look at the picture marked "Getreidespeicherhallen auf der A4 bei Weissenberg" and the one immediately beneath it.
Also, there's a picture that would appear to be the 2-lane bit near Dresden you mentioned and the caption states (incorrectly, from what you said) that this was the A4.
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Murphy
write out 100 times
I must not repeat what I see on the Discovery Channel
I must not repeat what I see on the Discovery Channel
I must not repeat what I see on the Discovery Channel
I must not repeat what I see on the Discovery Channel
...........................
MTC
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I agree that variable speed limit signs could allow for speeds of 80 or 90 mph but nobody's going to equip all our motorways with such signs just to allow car drivers to go faster! I can't see the conditions on the M25 ever being suitable to allow the signs to read '80' or '90'!
In the days before the 70 mph limit, it's true that Jaguar test drivers regularly drove E-Types at 150 mph on the M1 and fast cars were driven at high speed. But most ordinary cars were flat out at 80 mph or 90 mph while some could onlly just struggle up to 70!
Now most cars will do 100+ mph, many will do 150 and the '200mph club' has a growing membership. So limitless motorways are a pipe dream.
Cars use more fuel if they go faster, so it would be environmentally unsound to increase the limit beyond a strictly enforced 80mph.
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An arbitrary figure pulled out of your hat, Sofa Spud? A diesel 1.9 doing 100 will use less fuel than a 6 litre doing 35..... so where's the logic in your statement?
I think people tens to forget in these nannyed, ambulance-chasing "nothing's my fault I want to go on Jeremy Kyle" times that the whole point of a road is to get you from A to B as quickly as possible......
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Arbitrary? Hardly. Wind resistance builds up with speed, is the dominating factor at any significant speed, and it's not linear. What I mean is, a 20% increase in speed generates a lot more than a 20% increase in drag.
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Who cares about drag? It's fuel consumption that's important. Make a 6 litre Ferrari with a CD of 0.20 and it'll still use more fuel than my A3 (which is a 2 litre not a 1.9 as I said, sorry had a flashback to my old one!) at any speed you can think of. Drag is only a factor in relation to something else, "using" wind doesn't use up any resource, only the burning of fuel is a use of resources. Efficiency cannot be restricted to one area.
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Drag is what's burning your fuel!!! Any particular car will be more or less efficient. It will use vastly more fuel at 100, say, than at 70, and that's because of drag. "using" wind, as you so strangely put it, is actually using fuel - the drag needs to be overcome by burning fuel. This is quite simple, and it's straightforward to isolate it from any other factors being discussed - it applies to any vehicle with any drag coefficient and using any fuel or engine type.
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No, the engine is burning the fuel at a rate dictated by several changing factors, of which drag is but one. Yes, I agree that there is a non-linear increase as speed increases, but SURELY it would make more sense to design efficient power units that use less fuel across their performance spectrum rather than imposing an 80mph limit across the board whcih doesn't take into account ALL contributory factors?
As I said, the whole point of most travel is to get from point A to point B as quickly as possible. We have develoiped over the last 110 years a whole load of strange emotional knee-jerk reactions to speed and travel generally that if looked at logically and objectively, don't make that much sense. To take your argument to it's nth degree, we'd be better off travelling everywhere at 20mph or indeed returning to the Dark Ages and not travelling at all. Who's going to do that? We need to accept that in the absence of a better system, we use the petrol burning engine at the moment, and we need to make it as efficient as possible without making it a chore and a burden to travel.
Anyone agree, or am I on my own here?
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Hang on, don't take my argument as we should all go at 20!!! It's a trade-off, there's a need to get there quickly, but without excessive risk to yourself or others, and without disproportionate loading on finite resources.
The only point I was making is that above a certain speed, aerodynamic drag is the predominant factor in fuel use. A more efficient engine won't change that, you will still need to be producing a certain, exponentially increasing power output to overcome drag as your speed increases.
There was a very funny program on R4 last night in the 18:30 comedy slot. It featured 'Common Sense Man' ranting at one point. I mention it as he said something along the lines of:
"People say that the planet isn't inherited from your parents, it's borrowed from your children, so we should look after it. Well, my children borrow things from me all the time, and they always come back trashed, so frankly, this is payback."
In terms of fuel usage, I tend tho think that there is a trade-off, and I'd rather not use disproportionally more than I have to. I worked ou tI could save £400 a year by averaging 75 not 85 on the motorway, so I do that for my own financial gain. Whether you think that the speed limit has or should have an environmental aspect to it is a matter of personal opinion. My view is that it shuold be increased to 80, but not beyond. I fully accept that others may disagree.
In any case, the selfish argument can be taken further. Apparently it's pretty easy to tune most petrol engines to get ludicrous MPG, but in doing so you send NOX emissions through the roof. A commentator on the Prius a few months back mentioned that they had done so to a mini, getting 100+ mpg, but you could feel your lungs tightening if you were anywhere near it. So, we don't do that, at personal financial cost, because the societal cost would be too high.
I hope that?s made my reasoning clearer.
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I like the "Common sense Man" rant.... : )
I didn't know that about NOX emissions.... an interesting fact. Yes, it makes your reasoning clearer, and I see what you're getting at.... pity tightening up on mpg doesn't always have a beneficial outcome eh?
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it's pretty easy to tune most petrol engines to get ludicrous MPG, but in doing so you send NOX emissions through the roof. A commentator on the Prius a few months back mentioned that they had done so to a mini, getting 100+ mpg, but you could feel your lungs tightening if you were anywhere near it.
Do you know where I could read some more information on that?
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>>Do you know where I could read some more information on that?
Search for lean burn, and find out a promising technology cut short by stupid politicians in their headlong rush to be seen to be doing something. Grrrr.
Number_Cruncher
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>>Do you know where I could read some more information on that? Search for lean burn, and find out a promising technology cut short by stupid politicians in their headlong rush to be seen to be doing something. Grrrr. Number_Cruncher
Agreed. In the early 90s Rover demonstrated how a non cat lean burn Metro 16v K-Series GTi could be tuned to produce less CO, CO2 and NoX than a cat equipped equivalent car, one of the TV progs, Top Gear IIRC (or perhaps Tomorrows World), took both cars for a run over a fixed route and agreed that the lean burn car was better to drive, more economical and cleaner, the government didn't listen.
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"the government didn't listen."
Nothing changes then.
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An arbitrary figure pulled out of your hat, Sofa Spud? A diesel 1.9 doing 100 will use less fuel than a 6 litre doing 35..... so where's the logic in your statement? I think people tens to forget in these nannyed, ambulance-chasing "nothing's my fault I want to go on Jeremy Kyle" times that the whole point of a road is to get you from A to B as quickly as possible......
Well said!
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Steveid and Gordon M.
You are both right, of course Steve's A3 (1.9 or 2.0) would use less fuel at 70 than at 100 as would a 6 ltr Ferrari however if Steve was able to travel at 100mph he would have a shorter journey so he would be on the road for less time which would contribute to reduced traffic density which would make fuel and time wasting jams less likely, after all 1000 cars sitting at idle for 5 mins "waste" a hell of a lot of fuel and burn it ineffciently compared to cruising speed so have an even greater effect in CO and CO2 terms.
Higher speed has many, many benefits and two key disadvantages, energy efficiency (as mentioned above) and safety, the main percieved disadvantage is that increased speed equals increased risk however it is a matter of managing the risk so it does not increase with speed so as to take advantage of the other benefits of faster journey times. The reduced trafffic density, that faster journey times would bring, alone does a lot to offset the increased risk from higher speed because traffic density is a contributory factor in accident rates almost on par with speed.
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Too...many...logical....arguments! I am overloaded. : )
No seriously, I agree with both Gordon M to a degree and Cheddar to a (slightly higher) degree.
One thing I think we can all take away (as South Park would say "I think we've all learned something today") is that we need to address congestion as much as anything else, an uncomfortable truth that will not go away. It's arbitrary, I guess, talking about going at 100 when in reality, one rarely can!
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In reality we are talking about raising average speed by single figure % to help alieviate congestion.
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Why not treat statistics and cause and effect in the manner of the popular press:
in France the limit is 80. French motorways are normally congenstion free. Ergo, we need to get rid of congestion by raising the limit to 80. :-)
Seriously, Cheddar, I think you have a point, and Stevied, I can see where you're coming from as well. Congestion is a very bad thing and benefits nobody. I'm wary of very high speed limits because of my experiences in Germany, but a higher limit, with a lower limit in wet or poor visibilty, seems to make a lot of sense to me.
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but a higher limit, with a lower limit in wet or poor visibilty, seems to make a lot of sense to me.
I have been advocating that approach for years, it is good to concurr.
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I sincerely hope that could work.. I think we need some PROPER training in motorway driving, though..... if people would accept that they have to be awake on the motorway and not just pick a lane and aim to destination we'd be in with a fighting chance. Also, we need to de-personalise driving a little: someone who wants to go faster than you isn't necessarily a "maniac": and just because 70mph is the law here doesn't mean that it is an immutable cosmic law, and that the plucky Brits have come up with the best speed limits.... it's a figure that was a reaction (over-reaction IMHO) to a situation that finished 30 years ago.
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I think you've hit the nail on the head. When I passed my test in 1990, I had had ZERO training on how to drive on a motorway. I made many many mistakes and
I think it should be mandatory for all new drivers to have lessons Before they are allowed to go solo on a motorway. Lessons should include...
1. Getting onto a Motorway.
2. Lane Usage and Discipline
3. Etiquette - No Tail Gating, signalling, pulling out before junction slip-ons to allow traffic to join motorway, etc..
4. Looking ahead - judging speeds and distances, knowing where you want to get off
5. Blind Spots and Motorbikes - Spacial Awareness
I for one am amazed - absolutely amazed - at the drivers coming down the M4 who reach Junction 4b (M25) and suddenly remember they need to get off. They nearly cause an accident by either almost stopping in the inside lane, crossing the hayshered lines at the last moment, or (and I see this very often) stopping on the hardshoulder, reversing back and crossing the Hayshered lines to join the slip off.
If drivers received this basic training, I think our motorways would be less congested and have fewer accidents.
In all fairness, maybe a programme should be rolled out to existing drivers to receive a minimum 1 hours motorway training
-------------------
VW Bora (51) 2.0 SE
VW Touran (54) 1.9 TDI
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Quote:
>>>An arbitrary figure pulled out of your hat, Sofa Spud? A diesel 1.9 doing 100 will use less fuel than a 6 litre doing 35..... so where's the logic in your statement?<<<
A parked jumbo jet with its engines stopped uses less fuel than a lawnmower - that seems to be what you're saying - where's the logic in that?
Quote:
>>>I think people tens to forget in these nannyed, ambulance-chasing "nothing's my fault I want to go on Jeremy Kyle" times that the whole point of a road is to get you from A to B as quickly as possible...... <<<
Within reason - but clearly there are other relevant factors or we'd all be driving rocket powered bulldozers!
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Sofa spud, I didn;t mean to sound pompous, which; rereading it, I do!!!! Sorry.
My point was merely that efficiency is due to various factors, of which speed is merely one, if you read the answers and my answers back further up, I do concede some points (BUT NOT ALL OF THEM!!! : ) )
On a far more important note, I want a rocket-powered bulldozer. Where can I obtain such a device?!
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It's an interesting theory that cars going faster means they are on the motorway for less time so capacity is increased.
I had never thought of it that way and if fact thought the opposite. The extra stopping distances needed at the faster speed would cut capacity at any time in my opinion. Maybe the effect is overall roughly neutral.
The problem is, most drivers can't leave a big enough gap, so the braking shockwave effect would probably be worse if average speeds are higher and jams get worse. I often think automatic disabling of everyones brakes on the motorway (except for an emergency override) would cut congention significantly and probably accidents too! It work even better with a compulsory steering wheel spike but I can't see that law getting passed.
I read in the paper the other day about politicians considering dropping the motorway limit to 60 for so-called environmental reasons. That said, I can't think of any other argument for doing it, but there are better places to start.
I agree with a post further up that the French system of 130/110 km/h in godd and bad weather is a sensible one. Maybe a push to convert the UK to kilometres could mean more chance of a continental speed limit.
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It's an interesting theory that cars going faster means they are on the motorway for less time so capacity is increased. I had never thought of it that way and if fact thought the opposite. The extra stopping distances needed at the faster speed would cut capacity at any time in my opinion. Maybe the effect is overall roughly neutral.
I think if the effect were charted it would be far from linear, the point is that the average speeds for cars on many motorways is well under 70mph even if some cars are exceeding the limit, the AA and RAC reckon a 60mph average for a motorway journey is doing well. So take a section that has an average speed of 50 mph, if that can be increased to just 60 a reduction in traffic density in the region of 20% can be achieved.
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IIRC the speed at which a road bears the highest volume of traffic is around 16mph (any traffic engineers out there to confirm) so increasing the speed limit WILL NOT reduce congestion - it will only increases the closing speed between you and the jam in front of you which is not a good idea.
That is why the average speed in London is around 16mph! The only way to keep average speeds up is to stop people getting onto the roads similar to what they do at several junctions on the M6 in Birmingham and one of the ideas years ago to reduce congestion on the M25 was to close half the junctions - but which half?
How about odd numbered cars on Mondays/Wednesdays/Fridays, even numbered on Tuesdays/Thursdays/Saturdays and anyone on a Sunday - might solve Ford's problems!
Bad idea, both of ours are even!
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IIRC the speed at which a road bears the highest volume of traffic is around 16mph (any traffic engineers out there to confirm) so increasing the speed limit WILL NOT reduce congestion -
You may be right re 16mph however 16mph on m/way is unnaccepatble for obvous reasons, the answer is a trade off between, reducing journey times, maximising road capacity, and reducing percieved congestion. I say perceived congestion because the traffic engineer may look at the 10,000 cars an hour passing nose-to-tail at 16mph and think, great, free flowing traffic however the drivers would percieve 16mph as a traffic jam.
As I said if the effect of average speed v congestion were charted it would be far from linear however there would be sections on the chart where increased average speed would pay dividends, raising the average from 50 to 60 would require little additional gap between vehicles though could on some stretches of m/way massively reduce journey times and therefore ensure that there were less cars on the stretch at any one time.
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If sensible drivers leave a 2 second gap, you get a maximum 1800 cars per hour per lane - at whatever speed.
Only at relatively slow speeds are people happy to close up, and reduce the 2 second headway, so at slow speeds, it is possible to get more ars per hour through a lane - obviously in this slow speed regime, there is a trade off between speed and gap, and I can therefore I believe the 16mph figure.
For these reasons, raising speed limits to combat congestion is IMO, a non-starter.
Number_Cruncher
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It is not a matter of raising limits per se, rather taking a number of steps to ensure the free flow of traffic and therefore raise average speeds point to point.
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"Ars per hour": sounds like a fantastic unit of measure for motorway driving!
"The M6 was chocka today. It was SO annoying: 140 ars, I'd say".
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"Cars use more fuel if they go faster, so it would be environmentally unsound to increase the limit beyond a strictly enforced 80mph."
It uses even more fuel driving the buggy up and down a section a few times checking for nasties, before maxing it!
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"Cars use more fuel if they go faster, >>
Cars use more fule when they are stationary, 100's of them is a traffic jam.
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