...would you slow down to meet it. Thinking of the long straight greenways mainly.
CityCyclingEdinburgh Forum » Debate!
If the speed limit was 20mph...
(39 posts)-
Posted 12 years ago #
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This is tricky since I don't have a speedo on my bike. How are speed limits actually enforced for none motorized traffic anyway ?
Posted 12 years ago # -
They're not... Speed limits only apply to motorised traffic.
Posted 12 years ago # -
No. Car speeds should be limited because of the danger they pose to other pedestrians and other road users when they hit them. A 1 tonne car travelling at 20mph has 12 times the kinetic energy as an 80kg bike/rider combo at 20mph. The bicycle would have to reach 69mph to have the same kinetic energy as the 20mph car. It would have to reach 102mph to be equivalent of 30mph car and 171mph for a 50mph car!
Posted 12 years ago # -
Is this in/on infernal combustion powered devices or under my own power, if the former then Aye, if the latter, Naw... :)
Posted 12 years ago # -
In Dalkeith, there is a section of 20mph by the schools campus. Just by that there is a really nice steep hill. It is really easy there to exceed the 30 mph limit then the 20mph limit. However on the flat I would generally not be exceeding 20mph unless I was in a rush or training.
In the 20 mph zones, virtually no vehicles sit behind me if I am doing 20mph or thereabouts and many probably go more than 30. I have never seen any enforcement.
Posted 12 years ago # -
I certainly wouldn't if the traffic wasn't doing <20mph.
If it was going slower than 20mph I might be tempted to pass, but probably not unless it was going so much slower than 20mph that I wouldn't have to go over 20mph to get past anyway.
Bit of an edge condition?
Posted 12 years ago # -
I think that cyclists who disregard speed limits are at best hypocritical, whether speed limits 'actually' apply to cyclists or not - I suspect they don't apply because of a technicality, ie bad wording rather than by policy to deliberately exempt cyclists.
How can we possibly criticise other road users when we are not prepared to abide by limits ourselves? ...And we do constantly criticise other road users for breaking speed limits etc.
We also seem to 'strive' for equal status as road users (ie lets not have labels for cyclists, motorists, we are all road users). Or do we 'strive' for equal status so long as we don't have to follow all of the rules?Although cyclists are technically exempt from speed limits, you can be prosecuted simply for cycling too fast - under the charge of 'cycling furiously'. (from http://www.astounding.org.uk/ian/cyclelaw/speed_limits.html).
Posted 12 years ago # -
"I think that cyclists who disregard speed limits are at best hypocritical, whether speed limits 'actually' apply to cyclists or not - I suspect they don't apply because of a technicality, ie bad wording rather than by policy to deliberately exempt cyclists"
Nope, the wording is pretty clear, stating speed limits apply to 'motorised' vehicles, something which is repeated, and if it was just poor drafting then the legislation would have been amended by now.
The simple fact of the matter is, as has been pointed out above, a speeding car carries a HUGE amount more energy into a collision than a 'speeding' cyclist. This is one of the reasons for the anomaly. The other reason is that there is no legal requirement for a bicycle to have a speedometer, and so it is not actually possible to tell how fast you are going.
As you say:
"We also seem to 'strive' for equal status as road users (ie lets not have labels for cyclists, motorists, we are all road users). Or do we 'strive' for equal status so long as we don't have to follow all of the rules?"
that presumes (and I may be wrong) that you do believe we should all, as road users, abide by the same rules, and therefore all bicycles should carry speedometers and licence plates and fixed lights? And cyclists should wear helmets that conform to motorcycle standards?
There are carve outs all over the place depending on which mode of transport you have (indeed, speed limits are different between lorries and cars, to go back to the speed limit example - is a car driver in a 70 zone, driving at 70, hypocritical if he complains about a lorry driver driving at 70 in the same area?) precisely because the modes of transport are different from each other in terms of mass, potential speed, potential damage etc.
Posted 12 years ago # -
I was riding my bicycle furiously on Wednesday. Deliberately. As furiously as possible.
I don't see speed limits as being put there to control traffic flow or journey times (or, segments of the press and motoring lobby see it as part of the "war on the motorist"). I see that they are put there for safety purposes. A bicycle at 20mph is a lot less dangerous than a car at 20mph is a lot less dangerous than an HGV at 20mph.
I don't see that bicycles need their speed regulated or legislated as they just don't carry anywhere near the risk that cars and other motor vehicles at speed do. I'd say for a lot of riders they will rarely go over 20mph on a flat without wind assist. For me, it's about comfortable cruising speed in a light headwind on a flat. In town, even when tailwinds and gradients conspire with me, cruising speed is unlikely to get much above 25 over any distance.
Posted 12 years ago # -
Hi. I notice some have raised the valid point of the energy possessed by different vehicles at different speeds. However, no-one has yet raised the point that the pressure applied to bodies during a collision is inversely proportional to the area across which it is spread. I think some cars manufacturers even go so far as to design part to crumple in the event of a collision to protect pedestrians as well as the car occupants (no idea how common this is). In any case, I'd rather bang my head on a bonnet (under my own power) than on a handlebar. That said, I don't know which would actually do more damage to a pedestrian in a collision at a given speed. Both would be quite unpleasant.
Posted 12 years ago # -
Helmets for pedestrians I guess.
Posted 12 years ago # -
Or unlimited speed segregated cycle lanes...!!
Posted 12 years ago # -
Nice little calculator here (http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html#cc3).
A 100kg object (person + bike), travelling at 30mph would have an impact force of over 3.3 tons in a collision. At 20mph it would be less than 1.5 tons.Neither bikes nor cars are dangerous, the problem with both is when you introduce people who imagine that they do not pose any danger!
Posted 12 years ago # -
or 25 or 11 tons respectively for a small/medium (750kg) car...
Whereas even my heaviest bike and I only weigh around 82kg which at 30mph the calculator says would provide 2.7 tons of force, funnily enough the same force as that generated by our 750kg car travelling at 10mph!
So does this mean that I should be limited to 30mph and cars to 10mph or merely that statistics can be made to show almost anything if one tries hard enough? ;-)
Posted 12 years ago # -
Of course you're correct, 2.7 tons of force is nothing, would produce nothing more rhan a scratch. Just dust yourself, and the pedestrian you hit off and be on your way. Sigh!
Posted 12 years ago # -
2.7 tonnes of force could result in no injury, or be fatal, there are many more factors than that alone, without even venturing down the dark alleys of chance and probability!
The point is that the figure alone is meaningless, statistics which I find far more compelling are the number of people killed or seriously injured by bicycles each year (so small as to be statistically meaningless) compared against the number killed daily bu motor vehicles (hard to pin down but every figure I've seen is in the "appalling" range).Put bluntly, bicycles don't kill enough people to merit enforcement of speed legislation.
Posted 12 years ago # -
I still say that, by law, recumbents should require a man in a top hat waving a red flag to walk in front of them
Posted 12 years ago # -
Unlikely, my cruising speed without luggage is between 20-25 mph these days on the bent, the man with the flag better be on a motorbike!
Posted 12 years ago # -
you can have a durney bike then! Principle still applies
Posted 12 years ago # -
What's the hurry?
Posted 12 years ago # -
good point, tho in my case Im not rushing, its just that after carting the trailer around an unladen bike seems to take off of its own accord!
answer 2: you don't get a rush when you get over 20? I get a huge rush just from the acceleration, nevermind cornering at that speed.
Posted 12 years ago # -
Portsmouth council have introduced a 20mph scheme, they are of the opinion that the limit applies 'all' road users.(http://www.portsmouth.gov.uk/living/9727.html)
Wonder if Edinburgh will take the same position?
Posted 12 years ago # -
Yeah I probably would - only place I hit above 25 is Dundas St anyway, the rest of the way I wouldn't be slowing down too much 3-5 mph at most
Posted 12 years ago # -
Does 20mph also apply to cyclists?
The speed limit applies to all road users including cyclists.
Interesting. Without, once more, getting into the debate on the actual damage that can be caused... The statement The speed limit applies to all road users including cyclists is factually, and legally, incorrect.
Certainly the council is 'of the opinion' that the limit applies to all road users. But. It doesn't.
Okay, quick practical question. For speed limits to apply to bicycles then, obviously this will require all bikes to be fitted with speedometers. There is no way that you can apply a speed limit to a group on the road who are at the moment entirely unaware of what speed they are travelling at. So, if it's law that all bikes have to have speedos then those speedos will have to be correctly calibrated (as they are for cars) which will require a regime for regular testing (much like the MOT). I guess the question is this, in order for speed limits to apply to bikes, is any cost/benefit analysis likely to come out in favour of an expensive monitoring/testing/recording regime? I'm not saying that fast bikes can't do harm, obviously they can, but at what point does that harm become 'acceptable'?
Put it this way, less people are harmed every year by errant cyclists (or riding bicycles) than falling down stairs.
It's difficult to put this in a way that doesn't sound like 'I want to ride as fast as I like wherever I like'. Trust me, that's not what I think, and I slow down where I may come into conflict and thereby cause harm to others. But I just don't see there being some massive benefot to enforcing speed limits against cyclists (and if the counter to that is Try telling that to the 100 people run over by bikes and seriously hurt this year then I suggest if we are accepting that argument that we draw a line upwards from there and set out to seriously legally mitigate any activity that seriously hurts anyone - then see how ridiculous people think it is when it's suggested that all flights of stairs are replaced with ramps or are limited to one person walking on them at a time...).
Where was I? Oh yes. Portsmouth Council, commonly misconceived notion, but factually/legally wrong.
Posted 12 years ago # -
Actually, like spytefear/spitfire this is a bit of a theoretical moot point for me. A few hills I hit 30 on, but all in 30 zones. 20 zones tend to be in residential, non-hilly spots (cue 73 examples in the city of hilly 20 zones) and my flat cruising speed without a tailwind isn't likely to be above 20 anyway (and closer to 17-18mph).
Posted 12 years ago # -
But without a lot more enthusiasm in the enforcement of limits it will mainly be a paper exercise anyway.
I travelled most of the way from Craiglockart Junction down to the canal at around 30mph on the LHT yesterday evening (and my bike speedo is accurate so an average car speedo would be indicating around 32-35mph) yet had an impatient car close behind most of the way because he *had* to overtake me (sigh).
It doesn't take much of a slope/tailwind to make 30mph relatively easy on many bikes, even for a slowcoach like me, the little Dahon does get a bit twitchy above about 35 though! :-o
Certainly on flat roads though it's rare for me to exceed (reach!?) 20mph.
Posted 12 years ago # -
@Anth - Actually, like spytefear/spitfire
We are alike? I am finally complete ;)Posted 12 years ago # -
I have to say I think, if we're looking at speed limits as the potential they have for harm, then some sort of correlation between the limit and that harm isn't a bad idea (it's possibly why lorries have a lower limit on dual carriageways?).
So. In the city. 30 limit for bikes; 20 limit for cars; 15 limit for trucks; 10 limit for taxis... ;) The best thing about the plan is that cars and trucks can't get past the taxi doing 10mph, but bikes can. Mwuhahahaha!
I often wondered why the police didn't adopt a different strategy to speed limits (say on dual carriageways) by just sending two cop cars down the dual carriageway side-by-side at 70mph.
Posted 12 years ago # -
@Anth, A seductive theory, limits based on potential for harm, I just struggle to see why a 10 ton truck may only do 40mph on a single carriageway 60mph while a 10ton coach full of passengers is allowed to do 60mph, potential for injury loss of life? Far greater for the coach I'd have thought on the whole?
No, I rather suspect we have arrived at the current set of restrictions through reactive, politically expedient and often ill informed/advised legislation, some of which was reasonable at the time but is now outdated and some of which was never particularly sensible. On the whole, it works, that is not to say however that it could not be improved.
imho...
Posted 12 years ago #
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