[Closed] Institute of Advanced Motorists - cycling poll

I hear what you are saying glenp, just because I disagree does not make me wrong.

My point is that if all drivers are closer together then more cars get through before the red light. You can't see past the driver who is 2s ahead either - and the bigger gap allows more stuff to happen in it.

All applying only to congested city driving of course, and I'm saying I'm right per se, I just don't see that you are (in those narrow circumstances).

12-23M at 20-30mph - fair enough, not generally complied with I'd say.

As 30 mph is around 13 m/s so 23 m gap is almost two seconds! 12 m at 20 mph is 1 1/2 seconds. Try counting the time gaps or looking at the distance.

The bigger gaps and slower top speed giving higher average speeds is well proven - its by reducing bunching up. Cars speed up and slow down less so average speeds are higher - not always and not always significant but its a well known phenomonon on congested roads - no nmatter the speed limit

I think to a degree you are arguing against something that you haven't tried. I'm not talking about crawling inner city traffic, but actually 2 seconds is still is reasonable gap under any circumstances.

Here's an example that actually happened to a friend of mine who does drive too close (and cycles, so he really should see sense, but can't for some reason). He was following a car along an A road at night and the car in front swerved unexpectedly to avoid a cyclist. So my friend then is also swerving on his reactions to avoid the same. Luckily nothing was coming the other way so all was well, but all my mate could say to me was that the cyclist was not visible enough, not admitting that if he'd been a few seconds further back down the road not only would he have had much more time to deal with it but probably would have seen the bike for himself.

I reckon a number of seconds gap is not really a practical way of putting it, because you do (I admit) kind of get drawn into moving queues sometimes. Better to just make your priority number one to maximise the space around your vehicle. If you haven't tried it for a few months you just won't realise how much better it is. If you do try it and get used to it you will never go back.

glenp - your example is on an A-road.

Cars speed up and slow down less so average speeds are higher - not always and not always significant but its a well known phenomonon on congested roads - no nmatter the speed limit

Even for a short stretch between traffic lights?

Can both of you wake up to the fact that that's what I'm talking about?

Al You are right of course. Everyone else is wrong as is all the research.

Please show me the research that relates to the situation I have been discussing (rather than yours).

Yes, even for the short stretch between lights - if you go with the flow and don't rush you may even get the "green wave" effect.

Well, we've gone off topic really. The point was that bad driving goes unnoticed, whereas bad cycling gets the opposite sort of attention - ie people remember instances of bad cycling because it confirms the bias that is constantly reinforced in the media and elsewhere.

For heavy urban areas, town high streets etc, I would like 20mph limits - then you just roll along gently rather than racing to the next red light.

IMO there is no solution to this via legislation; applying the same rules to bicycles that are enforced on cars just doesn't work.

I commute daily through Cambridge, a city with a quite a few cyclists and a larger number of idiots on bicycles. I generalize somewhat but the "cyclists" are in hi-viz jackets, stop at red lights and have a bike with working brakes and lights; the others don't and it really winds up the motorists. Since the average motorist cannot distinguish between the two groups on bikes they decides we're all as bad as each other. So I've been the brunt of motorist's frustrations on a handful of occasions without any provocation on my behalf. C'est a vie.

But here is the rub. On a bike in this city I feel significantly more at danger from other people on bikes than I do with cars. Sure the cars have the potential to inflict greater injury, but they are generally stationary in traffic or moving in a predictable manner.

Then there is summer with the massive increase in hire bikes. Lethal. How does the training and licensing solve this problem? It doesn't. Yellow sticker on the down tube = accident imminent.

I've had far more close calls with motor vehicles than people on bikes in Cambridge.

I am generally passing other rides so I can assume they're idiots and give them a wide berth.

I regularly have vans and buses half overtake and then try to squeeze me off the road when something comes the other way. Its less frequent with cars as they can normally fit into the bits of road they want to occupy.

In addition to safety, there are other potential benefits to be gained by speed limit reductions in
urban areas. Those suggested in the literature include an increase in traffic flow and consequent
reduction in congestion and delays, [b]particularly where the roads are functioning at near capacity.[/b]
Further, reductions in speed bring about a reduction in vehicle operating costs with less wear and
greater energy (fuel) efficiency, and less pollution and noise (see e.g. Carlsson, 1997; Kallberg and
Toivanen, 1998; Cameron, 2000; Elvik and Vaa, 2004).

You can follow the references from here if you want to

Then there is summer with the massive increase in hire bikes. [b]Lethal[/b]

how many are routinely killed in this way every year in Cambridge ?

TandemJeremy - Member
In addition to safety, there are other [u]potential[/u] benefits to be gained by speed limit reductions in
urban areas. Those suggested in the literature include an increase in traffic flow and consequent
reduction in congestion and delays, particularly where the roads are functioning at near capacity.
Further, reductions in speed bring about a reduction in vehicle operating costs with less wear and
greater energy (fuel) efficiency, and less pollution and noise (see e.g. Carlsson, 1997; Kallberg and
Toivanen, 1998; Cameron, 2000; Elvik and Vaa, 2004).

Cheers I'll try and get a read of that - interesting qualifier underlined as above - I recall this was how you qualified the £500 death-trap argument?

Its just the first referenced stuff I could find on this - hoever if you follow the citations and references you should be able to find more.

Its morre obvious on congested motorways but the same effects work on congested urban roads.

Its one of those things that really irriate me - 20 mph limits on urban streets will have little overall effect on total journey times, decrease polution and make cycling safer as well as reducing pedsetrian casualties - but because it goes against the "common sense" of the road lobby it will never happen

Here's my tuppence worth:

I filled in the survey. I said there should be more police making cyclists obey the law (because I don't see why cyclists should deliberately jump red lights). I said there should not be cycle licensing. I said that drivers should be trained on judging the speed of a bike and should learn the Highway Code on entering cycle lanes and overtaking cyclists.

Here's a couple of observations (I commute in London btw and have done since 1987 - with a 10 year break - when I commuted in rural N Northumberland and then from Gala to Edinburgh)

I was on a bus one day and a group of girls were talking, one complained "I've taken my driving test four times and still haven't passed" - the others empathised. They did not seem to understand that driving is a skill and a driving licence must be earned, and is not awarded as of right. She did not countenance the possibility that she might simply have been a rubbish driver.

People take the same kind of liberties when I am in my car (a MASSIVE 4x4) as they do when I'm on my bike. My conclusion? People generally don't think, don't give a sh1t, have somehow abdicated responsibility for their actions.

Thing is, when I'm in my car; they will lose, when I'm on my bike, they may very well win.

2 seconds? I wish! If you leave more than a gnat's c0ck, someone will pull into the gap.

And don't get me started on the idiots who pull into my braking space when I am towing my caravan.

Its one of those things that really irriate me - 20 mph limits on urban streets will have little overall effect on total journey times, decrease polution

I said there should be more police making cyclists obey the law (because I don't see why cyclists should deliberately jump red lights).

I agree with your point about people thinking there is some sort of right to drive. Personally I reckon that having failed 4 times suggests there's something basic you're not getting, so maybe you should have to wait a year or two before trying again (as to people who've failed tens of times - they should probably never be allowed to drive simply because they freakishly managed to be competent for half an hour at some future point, before inevitably reverting to being rubbish). I'm sure I'll be accused of being very right wing for comments like that! Not that the skills to pass a test are necessarily that much of a challenge to young men (and boys) who'll then be irresponsible on the roads - I should know, I passed first time at 17 😉

aracer - yes, I take your point re the police.

I am a motorist and a cyclist. In my car I am tagged via my numberplate, on my bike I am anonymous.

The thing about cyclists jumping red lights is this, I don't jump red lights so I am next to the cars and I can see the fury in motorists' eyes. Motorists already feel hard done by and feel they have bought some kind of right to be on the road. Cyclists are seen to be getting off lightly - tax wise - yes I know roads are funded from general taxation (not solely road fund licence), but you know what I mean.

As for numbers of times taking the test. I worked for a Greek solicitor whose elderly Greek mother had tried and failed her test in this country many many times. The Greek solicitor was proposing to send her mother home to Greece to take her test there, where it is easier, and her licence would then be valid here. How scary is that?

aracer - Member

I presume you'll point out that it would only take me 2 minutes more for the 2 miles of 30 limit I can usually do a steady 30 in? The fact my car (and most others) uses less fuel and generates less pollution at 30 than at 20 is undeniable though.

Rubbish and piffle as I showed last time. To accelerate to 20 mph takes less energy than to accelerate to 30 mph/

In congested streets journey times would not increase as is proven. Also it reduces pedestrian and cylist casualities. Streets are for all not just cars.

In a steady state the RAC managed to show a slight and insignificant increase -= even they admitted in stop start conditions less petrol and less pollution occur in a 20 mph limit.

I proved this to you last time we had this debate.

Edit - I would also give you more 40 limits if I ruled the world - congested urban with shops houses and cyclists - 20 mph. Open suburban where pedestrians cycles can be separated and right and left filter lanes possible - 40 mph.

The fact my car (and most others) uses less fuel and generates less pollution at 30 than at 20 is undeniable though

but if 20mph urban speed limits become the norm then car mnfrs (hopefully) will change the engine management systems / gearing to match this - wouldn't have thought a big deal - of course depends on buyer perception of the importance - one of my pet hates is that pedestrian safety ratings get little mention in car reviews

Why not make everyone applying for a provisional license take a formal cycling proficency test and pass it and under take several months of cycling prior to being let loose on the roads in a car? That way they would appreciate other road users and also develop an understanding of road craft from another users point of view.
May make them a bit fitter too....
Also it would increase the numbers of cycles on the road - safety in numbers and all that.

myheadsashed - Member
Why not make everyone applying for a provisional license take a formal cycling proficency test and pass it and under take several months of cycling prior to being let loose on the roads in a car?

Makes sense in theory, but you can bet that there would be a way round it, an opt-out for those who couldn't cycle for whatever reason, and [i]everybody[/i] would manage to get that opt-out.

Don't forget that to pass your test in this country it's not compulsory to drive on a motor way, in bad weather, on a countryside road lined with dry stone walls, etc, etc, etc. You can be a fantastic driver around your local area, on dry summer evenings, but that means nothing when you are driving across Dartmoor in a monsoon a few days later.

Even the simple fact that the Theory Test is based on a percentage scares me - how can you be allowed on the roads if you don't recognise some roadsigns in your test?

Wow. Gone from "potential" to "proven"?

Rubbish and piffle as I showed last time. To accelerate to 20 mph takes less energy than to accelerate to 30 mph

In congested streets journey times would not increase as is proven.

but if 20mph urban speed limits become the norm then car mnfrs (hopefully) will change the engine management systems / gearing to match this - wouldn't have thought a big deal

Oh I do love an argument ....

not sure if totally relying on future technology - plenty of small city cars around and more appearing all the time not big breakthrough in technology just a focus on matching engine output to need rather than performance - the trend already exists

plenty of small city cars around and more appearing all the time

A racer - your rac or AA link ( whichever it was) had the proof that you only use less petrol at a steady 30 mph and under ideal conditions. If you are accelerating and slowing then even that link / piece of research showed that you use more petrol in a 30 mph limit than a 20. Even the steady state its only some cars dependent on gearing.

to say otherwise is ludicrous. It takes 50 % more energy to accelerate to 30 mph than it does to 20 mph.

Hoist by your own petard

The AA accepts that targeted 20 mph speed limits in residential areas are popular and improve safety. [b]Along shorter roads with junctions and roundabouts, limiting acceleration to up to 20 mph reduces fuel consumption.[/b]

Now this is from an organisation and a piece of work that set out to discredit 20 mph limits. Even they have to accept that it actually reduces petrol consumption

http://www.theaa.com/public_affairs/news/20mph-roads-emissions.html

Here is some good real non biased research on 20 mph limits.

http://www.transportpolicy.org.uk/Future/20mph/20mph.htm

How many times do I have to say it before you read what I'm writing, TJ? Go back through my posts and find the bit where I say most of my driving in 30 limits is stop start. Can't find it? Well maybe that's because I can generally do a steady 30, and have been saying so all through this thread. That makes all your arguments irrelevant - for the driving I do in 30 limits, being restricted to 20 would mean I used more fuel, not less. Fact.

It takes 50 % more energy to accelerate to 30 mph than it does to 20 mph.

Even the steady state its only some cars dependent on gearing.

Though it seems you're happy to prove my point for me. Did you bother reading the links you've provided? I mean you picked one lonely sentence out of that AA report which doesn't disprove my point at all (do I need to remind you again that I'm not talking about stop/start driving), whilst it also has the following right at the top "On average, petrol car fuel consumption on longer and relatively free-flowing 20mph urban streets can worsen by 5.8 miles per gallon". Meanwhile the only actual evidence based fact in the other one is the graph which also shows that you use more fuel at 20 than 30. Yes I have read the surrounding text which is presumably what you're relying on, but all of that is just speculation, and has just about as much weight as what you're writing on this thread.

Though by introducing that web page as evidence, are you trying to make it a bit more obvious that you're just trolling? The idea that it's non biased is a joke surely? It's just about as non biased as what you're writing - just like you he's attempting to fit the available evidence to his viewpoint rather than basing conclusions on the evidence. If that's an example of the quality of his analytical thinking and use of data then I'd certainly not employ him. I'll go into more detail later, but try following his links and see whether what he claims for them supporting what he says is actually true.

[img] [/img]

Anyway (vain attempt to steer this thread back to the original point), I've done the survey and used the 'other' box to suggest compulsory cycle awarness training for all drivers. Suggest others do likewise instead of arguing/ winding each other up across the t'interweb.

There's a heavy disingenuous dose in the anti 20mph limits arguents, I suggest. Basically you just don't want to slow down. "I'm in the front of the queue" - yea ok. How do you manage to engineer it so you're always at the front of the traffic? And even if you do (which you don't) then all of the other cars don't get to be at the front. TJ makes some good points and provides good reference for the argument for ALL cars, not just the miraculous ones that always drive on the front of the traffic.

To claim that normal rules don't apply because you always drive at the front of the traffic, and then in the next paragraph to suggest that someone is selecting evidence to suit his argument is about as absurd as it gets.

[i]...used the 'other' box to suggest compulsory cycle awarness training for all drivers[/i]

How would that work? Just as part of the driving test? I suppose that would be a start, but you're never going to get all the existing drivers with that.

Nationwide TV and all other mainstream media campaign telling everyone that cyclists are on the road by right. They are not just borrowing the gutter section of the road that other vehicles don't drive on. Even if they were taxed the fee would be zero.

Nationwide campaign showing where a bike should be positioned on the road.

Nationwide campaign for responsible and good driving. Not just getting away with it and seemingly keeping within the law - actual proper driving. Keeping as big a gap as possible and driving in your own space. Constant alertness and respect for other people. Same goes for cyclists, but car drivers have to realise that their standards stink too.

Problem solved.

TJ and GlenP both put it well.

Al seems to be thinking that 20mph zones are all about hindering him from driving at 30mph in a 30mph zone (not sure if that is quite the best driving habit for a start).

Reducing overall speed makes the whole road area, including pavements, safer for pedestrians, safer for cyclists on the road and may help to encourage even more cyclists to take to the roads as they feel safer. Increasing numbers of cyclists on the road mean less drivers, further reducing traffic noise, pollution etc.

I could continue, but I feel that Al will miss the point (again)...

TJ and GlenP both put it well.

Al seems to be thinking that 20mph zones are all about hindering him from driving at 30mph in a 30mph zone (not sure if that is quite the best driving habit for a start).

Reducing overall speed makes the whole road area, including pavements, safer for pedestrians, safer for cyclists on the road and may help to encourage even more cyclists to take to the roads as they feel safer. Increasing numbers of cyclists on the road mean less drivers, further reducing traffic noise, pollution etc.

I could continue, but I feel that Al will miss the point (again)...

I guess I am thinking about my commute - several stretches of busy but wide road where 30mph is IMO reasonable, with lights around a mile apart.

Al. No-one is suggesting converting all 30mph limit areas to 20mph. Just some of them.

We've had five (I think, it could be more) pedestrian deaths in little old Dorking in very recent years, including a friend of mine. Nothing is certain, but pretty sure that 20mph would have left all of them alive and delayed traffic to the tune of about two minutes for each pass of the High Street and one way system. We could probably also get rid of some of the bloody silly traffic lights which only got put in because drivers are too selfish and impatient to let traffic filter over junctions. If we all filtered slowly through intersections, allowing one car through each, then we wouldn't feel the need to accelerate between lights in the first place.

There's a heavy disingenuous dose in the anti 20mph limits arguents, I suggest. Basically you just don't want to slow down.

"I'm in the front of the queue" - yea ok. How do you manage to engineer it so you're always at the front of the traffic? And even if you do (which you don't) then all of the other cars don't get to be at the front. TJ makes some good points and provides good reference for the argument for ALL cars, not just the miraculous ones that always drive on the front of the traffic.

Al. No-one is suggesting converting all 30mph limit areas to 20mph. Just some of them.

It is disingenuous because rather than just admit that you plain don't want to slow down you feel like you need to clutch at some frankly very tenuous other arguments to justify your position. I think disingenuous is the right word for that.

20ph limits are suggested for certain areas, not as a substitute for all 30s.

Nothing you say is "too subtle for me". Actually, nothing you have said is subtle at all.

Just because you drive at 30 doesn't put you at the front of the queue at the lights. Nonsense.

Al. No-one is suggesting converting all 30mph limit areas to 20mph. Just some of them.

Oh. I thought that was pretty much exactly what TJ was advocating.

[b]Nothing is certain[/b], but [b]pretty sure[/b] that 20mph would have left all of them alive

LOL!

Glad your laughing. Actually, no. What's so funny about people being dead when they wouldn't otherwise be just because drivers are selfish?

IIRC the US has a charge called 'vehicular manslaughter' - wonder if we could have a charge worded similarly?

It is disingenuous because rather than just admit that you plain don't want to slow down you feel like you need to clutch at some frankly very tenuous other arguments to justify your position

Nothing you say is "too subtle for me". Actually, nothing you have said is subtle at all.

Just because you drive at 30 doesn't put you at the front of the queue at the lights. Nonsense.

GlenP - don't you understand that someones journey is FAR more important than another persons safety?

glenp I was commenting on your debating style, get a grip!

Because of course driving at 30 on wide straight roads with good sightlines and few pedestrians on the pavements is FAR more dangerous than driving at 20. Silly me.

al - I know you were trying to laugh at my phrase - but you also know what I meant by "pretty sure". I could spell it out - you are much less likely to die if hit at 20 than 30. You won't definitiely survive, but your chances are much higher. But you knew that, you were just being, er, you.

aracer - again you make stupid comparisons. Wide straight roads without pedestrians are not really what we are talking about. It is places like High Streets and residential roads that 20 would be much better. Actually, the limit is only a maximum - you might want to try rolling along at 20 next time the pavement is full of pedestrians and there are folk trying to cross the road and so-on. Once you get used to it you'll wonder why you didn't try it sooner.

"So pointing out that you'll use more fuel and generate more pollution travelling at 20 rather than 30 is a tenuous argument"

i doubt this has a significant effect when many urban roads are full of traffic lights and junctions anyway. constant stop/start driving will have far more of an effect on fuel consumption than speed.

In london i counted around 10 traffic lights per mile.

<sigh> go back and read my posts properly, HH. Not everybody lives in London (or Edinburgh) - I can drive for 4 or 5 miles in 30 limits through the middle of Malvern with a traffic light density of exactly 0 per mile.

glenp - I'll bet at least one of the long straight roads I drove down at 30mph today would be on TJ's list. That being a road with pavements set well back from the road behind big verges. Can't actually remember the last time I drove down the road with pavements full of peds, though I'll be sure to come back to you in 5 years or so when I next do.

BTW have you worked out my queues yet?

All I've worked out is that the kind of arterial 30 limit road that you're talking about, with pedestrians well separated from the road by verges, good visibilty, not many traffic lights etc, is not going to be a target for a 20mph limit.

So all of this discussion is completely pointless. You're talking about conditions completely different to those meriting a 20mph limit. You are using your own very specific example of roads not warranting a 20mph limit to try and put a case against 20mph limits in general.

Anywhere with rows of shops, kids playing next to the road, schools, difficult visibility, and other factors that make it not a dead straight roll-along would however be a good place to [i]consider[/i] a 20mph limit. The stop-start nature of those roads plus the major safety benefits would defeat the slightly reduced mpg arguments.

Ah, so it was actually too subtle for you then.

I'm not convinced most people would describe many of the roads I'm talking about as "arterial" even though there isn't a safety issue with doing 30 along them.

You are using your own very specific example of roads not warranting a 20mph limit to try and put a case against 20mph limits in general.