# 20mph limits unenforceable?



## Randy Butternubs (17 Jul 2013)

Hi all. I recently went on a (motor) Bikesafe course run by the police. It was rather good and I recommend those of you with motorbikes to check it out. One of the officers said a couple of things I hadn't heard before which I thought were pretty significant.

There's been a lot of talk about 20 limits - they they're great and we should have more of them, or that they are useless in practice as they are rarely enforced. Or even that it's been publicly announced that a new 20 limit will not be enforced.
What I hadn't heard is that 20mph limits are legally impossible to enforce. Apparently car speedometers are only legally required to be accurate over 30mph. For this reason speed cameras in 20mph limits are set to trigger at 36mph as they are for 30mph limits. Given that most speedometers read optimistically to help prevent drivers from getting into trouble you would likely need to be traveling at an indicated 40mph to set off the camera!

The other thing he said was that, as of last week, red light cameras will now be triggered by (motor vehicle) ASL violations. This seems rather harsh to me as the penalty is apparently the same as if you jumped a light - 3 points and a (£60?) fine. It would be nice if it stopped people parking in them though.

I would be interested to know if anyone has heard anything about the above points and can confim/deny. Please weigh in with opinions too


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## StuartG (17 Jul 2013)

The study on the original London's 20 mph zones concluded that the real reduction in average speeds of around 10 mph was not due to enforcement (there wasn't any) but by calming measures. I had always thought that was the only way.

Until a couple of weeks ago I had to go all around Islington by car (don't ask). Lots of banners proclaiming it as the first 100% 20mph borough and the traffic was mostly respecting it despite no calming. Quite a surprise.

Of course there was the odd boy racer. But nothing will stop those guys short of a zap gun.


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## anyuser (17 Jul 2013)

Randy Butternubs said:


> The other thing he said was that, as of last week, red light cameras will now be triggered by (motor vehicle) ASL violations. This seems rather harsh to me as the penalty is apparently the same as if you jumped a light - 3 points and a (£60?) fine. It would be nice if it stopped people parking in them though.
> 
> I would be interested to know if anyone has heard anything about the above points and can confim/deny. Please weigh in with opinions too


 

I would be surprised if this was the case. Wouldn't they have to move the inductive loops/strips at all the junctions back to the first stop line?


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## Randy Butternubs (18 Jul 2013)

@ StuartG - You're right. I didn't mean to overstate the importance of enforced limits in reducing speed. I was also under the impression that traffic calming measures were necessary - it's a shame that the go to method seems to be bloody speed-bumps .

@ anyuser - Are you sure the cameras trigger from the induction loops? I assumed they used motion sensors like speed cameras(?)


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## Davidc (18 Jul 2013)

The red light cameras on a junction near here use motion sensors and operate if the lights are at single colour red. The only oddity if they're going to do ASL as well is that bikes set them off (i.e. make them flash)

I don't see enforcing ASLs as harsh, any more than enforcing any other aspect of traffic law. As I've often commented before, my view is that traffic offence penalties are very light so there's no grounds for complaint.

(My preferred penalty for RLJ would be a fixed £5000 fine and 12 months ban - and that's first offence. Cyclists would get the same but without the ban, speeding and drink drive would be at least double that. I have to drive 25,000 miles a year and want some protection, I ride a bike and the same applies.)


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## glasgowcyclist (19 Jul 2013)

Randy Butternubs said:


> What I hadn't heard is that 20mph limits are legally impossible to enforce. Apparently car speedometers are only legally required to be accurate over 30mph.


 
Regulation 35 Road Vehicles (Construction and Use) Regulations 1986 states that every motor vehicle shall be fitted with a speedometer except:
•a vehicle having a maximum speed not exceeding 25 m.p.h.,
•a vehicle which, at all times, is unlawful to drive at more than 25 m.p.h.,
•an agricultural motor vehicle driven at not more than 20 m.p.h.,
•a motor cycle not exceeding 100cc first used before 1st April 1984,
•an invalid carriage first used before 1st April 1984,
•a works truck first used before 1st April 1984,
•any vehicle first used before 1st October 1937,
•a vehicle fitted with an approved tachograph which is required or not.

Vehicles first used on or after 1st April 1984 the speedometer should be capable of indicating the speed in miles per hour and kilometres per hour. Vehicles may instead comply with EC Regulation (Community Directive) 97/39 or ECE Reg 39.
These directives stipulate the markings, graduations of the speedometer and refer to 75/443/EEC which specifies the tolerances.
The indicated speed must never be less than the true speed (it must read exact or high) and between 40km/h and 120km/h the error must not exceed 10% + 2.5 m.p.h. high (true speed/10 + 4kph).
This means at a true speed of 25mph or 40km/h the speedometer may read 40/10+4 = 8km/h or 5mph high = 30mph indicated.

My reading of the accuracy requirement above is that in all circumstances the speedometer must not show less than the true speed and _in addition_, where the speed is between the limts specified, the error level must not exceed 10% plus 2.5mph.

I think someone has misunderstood that to mean that there is no requirement for speedos to be accurate below 25mph. In my view that's wrong so I don't see why someone couldn't be prosecuted for exceeding a 20mph limit.

GC


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## anyuser (19 Jul 2013)

Randy Butternubs said:


> @ StuartG - You're right. I didn't mean to overstate the importance of enforced limits in reducing speed. I was also under the impression that traffic calming measures were necessary - it's a shame that the go to method seems to be bloody speed-bumps .
> 
> @ anyuser - Are you sure the cameras trigger from the induction loops? I assumed they used motion sensors like speed cameras(?)


 

I was going by this page
http://www.wmsafetycameras.co.uk/cameras_work.php?cameramovie=RedLight
They definitely say sensors 'in' the road which would be inductive I think. But I am open to being corrected


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## Dan B (19 Jul 2013)

Randy Butternubs said:


> .
> What I hadn't heard is that 20mph limits are legally impossible to enforce. Apparently car speedometers are only legally required to be accurate over 30mph.


Why should that make the limit unenforceable? You can be done for drink driving despite there being no legal requirement to carry a breath alcohol tester at all.


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## Mile195 (19 Jul 2013)

I couldn't confirm or deny whether or not they're enforceable. I do think they're a complete gimmick though. They exist mostly on back streets where you can't set speed traps anyway.

IMO all they've done by sticking them everywhere is make people used to seeing them, so now people don't take any notice of any of them.

I remember when I very first came across 20mph limits, because they were a rarity I assumed that there must be something important that warranted it, like a primary school or an accident blackspot, and you monitor your speed more closely as a result. I don't get the same impact now they're on every single side road - the signs have just become yet another ugly piece of road furniture.

I agree that traffic calming is more effective though. Well, when properly placed.


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## snailracer (19 Jul 2013)

AFAIK 20 mph limits are legally enforceable, it's just that most police forces decided they wouldn't because they got no extra funding to do so.


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## neil_merseyside (20 Jul 2013)

snailracer said:


> AFAIK 20 mph limits are legally enforceable, it's just that most police forces decided they wouldn't because they got no extra funding to do so.



I attend the odd cycle forum and indeed have heard that our (Wirral/Merseyside) police state that they will not regularly enforce the 20mph 'due to likely workload' (or some such wording) BUT that high profile occasional driving advice awareness teams would operate (using CPSO and volunteer residents etc) to 'flag' the change.

However most councillors/experts seemed confident that enough drivers would be decent and slow down, and as such would essentially cause compliance of others, as our 20 zones are all residential then most people actually seem happy to comply (local with kids?) and as none of the larger feeder roads are posted down from 30 then the 20 only affects the last few hundred yards of most peoples journey!

Obey/compliance in this context is 'the majority' at or about 'x speed' +y% error (over obv. !), so speed reduces by most of the reduction...


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## morrisman (21 Jul 2013)

The 20mph limit over Tower Bridge is enforced by average speed cameras.


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## deptfordmarmoset (21 Jul 2013)

Hmm, a little thought from the back streets of London: does using bumps to slow down vehicles *with suspension* and inconvenience cyclists (*usually without suspension*) really make good sense? And hands up if you've ever been forced out of your lane because there's a 4x4 driving head on at you in the middle of the road? To avoid those bumps...


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## Dan B (22 Jul 2013)

deptfordmarmoset said:


> Hmm, a little thought from the back streets of London: does using bumps to slow down vehicles *with suspension* and inconvenience cyclists (*usually without suspension*) really make good sense?


I habitually ride over speed bumps on a bike with no suspension at speeds greater than most car drivers will attempt. YMMV if you have dodgy knees or a large unsprung load that won't enjoy it (e.g. child in a bike seat) or maybe if you're on a recumbent and can't honk


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## dellzeqq (22 Jul 2013)

Dan B said:


> Why should that make the limit unenforceable? You can be done for drink driving despite there being no legal requirement to carry a breath alcohol tester at all.


 
quite. 

Next!


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## fudgepanda (18 Aug 2013)

anyuser said:


> I was going by this page
> http://www.wmsafetycameras.co.uk/cameras_work.php?cameramovie=RedLight
> They definitely say sensors 'in' the road which would be inductive I think. But I am open to being corrected


 
The term "Safety cameras" is used above. In Greater Manchester the 20 limit couldn't be enforced by those involved in the Safety Camera Partnership. Fixed Gatso cameras aren't appropriate for most 20mph roads and the kind of equipment (usually LTI 20/20 laser devices with 500mm Tamron lens) that are used from the pavement by TPCSOs don't really work at distances of below 50 -100 metres, which again renders them unsuitable. The only real chance of prosecuting drivers is if they're followed by a Police car or bike. If any driver was clocked in a 20 zone by one of those they'd have to be drunk or certifiably insane not to see a big white 4X4 with blue lights on the roof, in addition to which, the Cops usually like to follow a vehicle for about one third of a mile at an illegal speed which increases the chance the following vehicle will be spotted giving the driver time to slow down.


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## fudgepanda (18 Aug 2013)

Dan B said:


> Why should that make the limit unenforceable? You can be done for drink driving despite there being no legal requirement to carry a breath alcohol tester at all.


 
You do in France. I know we're not in France, but where one Euro state leads, the others often follow. Having said that, if you are driving then the best thing is to simply not drink alcohol at all, that way you can't be over the limit. However, it is a little difficult to drive somewhere if you don't move at all.


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## buggi (18 Aug 2013)

it isn't illegal for a car to stop in an ASL so i fail to see how they are going to treat that the same as running a red light. sounds to me like the cop doesn't know what he's talking about, and it wouldn't be the first time.


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## dellzeqq (18 Aug 2013)

buggi said:


> it isn't illegal for a car to stop in an ASL so i fail to see how they are going to treat that the same as running a red light. sounds to me like the cop doesn't know what he's talking about, and it wouldn't be the first time.


http://www.tfl.gov.uk/corporate/media/newscentre/28397.aspx 

the cops are enforcing ASLs in a big way down here - the going rate is sixty quid. I can only imagine that TfL has got it's Orders in place.


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## Dan B (18 Aug 2013)

fudgepanda said:


> Having said that, if you are driving then the best thing is to simply not drink alcohol at all, that way you can't be over the limit


And if you're unsure whether you're exceeding the speed limit, the best thing is simply to slow down until you're sure you're not. For most people this will not involve coming to a complete halt, and a reasonable argument could be made that anyone unaware whether they are e.g. exceeding walking pace while on their bike probably *should* be required to come to a complete halt ...


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## StuartG (18 Aug 2013)

dellzeqq said:


> ...the cops are enforcing ASLs in a big way down here - the going rate is sixty quid. I can only imagine that TfL has got it's Orders in place.


Not in SE26 sadly. The council just put in a spanking new set of ASLs. These are probably technically illegal for cyclists as there is no dashed entry point. But this has stopped cars on the very day after the BBC did a big thing on ASLs blocking the ASL two abreast EVERY time I went down there leaving me a bit exposed at the front. Thankfully the traffic turning into the road blocks the Yellow Hatch so stopping fast getaways taking you out. Doh!

I have a idea for a new FPN. Any police officer can stop and ask you 10 questions from the Highway Code (just like when you took your driving test). Get less than five and its a £30 fine and a re-test within 7 days. Fail to get 7 out of 10 on that one (as you had time for a quick revision) and its a £90 HC training course. Doesn't guarantee better driving and riding but at least it will be better informed driving and riding.

Watchafink?


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## Hill Wimp (18 Aug 2013)

Dan B said:


> Why should that make the limit unenforceable? You can be done for drink driving despite there being no legal requirement to carry a breath alcohol tester at all.


 
Yes but you get breath tested back at the Police Station then if you are over you get "done" as you say which is actually charged.


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## buggi (18 Aug 2013)

dellzeqq said:


> http://www.tfl.gov.uk/corporate/media/newscentre/28397.aspx
> 
> the cops are enforcing ASLs in a big way down here - the going rate is sixty quid. I can only imagine that TfL has got it's Orders in place.


 

That's weird... same organisation difference advice (skip to 0:54); it states both, that crossing the first and second stop line you are liable to a fine, but that if the lights change and you can't safely stop before the first line, you must stop before the second. Advice is confusing and contradictory, and gives any driver mitigation. They can just say "i couldn't safely stop before the first line so i stopped at the second"

View: http://www.youtube.com/watch?v=zbuo-rney-Q


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## glasgowcyclist (27 Sep 2013)

Randy Butternubs said:


> What I hadn't heard is that 20mph limits are legally impossible to enforce.
> 
> <snipped>
> 
> I would be interested to know if anyone has heard anything about the above points and can confim/deny.


 
They're enforceable.

_"Twenty's Plenty signs have recently been installed on the A72 outside Kingsland Primary in Peebles after a campaign by concerned parents.
Traffic police set up a hand-held speed trap near the school gates on Monday. 
The first vehicle they pulled over for allegedly breaking the limit was a bus carrying pupils on its way to nearby Peebles High School."_​ 
GC


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## Longshot (27 Sep 2013)

glasgowcyclist said:


> Vehicles first used on or after 1st April 1984 the speedometer should be capable of indicating the speed in miles per hour and kilometres per hour. Vehicles may instead comply with EC Regulation (Community Directive) 97/39 or ECE Reg 39.
> These directives stipulate the markings, graduations of the speedometer and refer to 75/443/EEC which specifies the tolerances.
> The indicated speed must never be less than the true speed (it must read exact or high) and between 40km/h and 120km/h the error must not exceed 10% + 2.5 m.p.h. high (true speed/10 + 4kph).
> This means at a true speed of 25mph or 40km/h the speedometer may read 40/10+4 = 8km/h or 5mph high = 30mph indicated.



Apologies for the threadjack but this point has always interested me.

Given that very few people could tell the difference between 30 and say 35 mph by eye whilst driving, how would a driver suspect that his speedo was inaccurate? The answer, I guess, is to ensure that it is tested/calibrated on a regular basis, but how regular would be deemed reasonable in court? Is it a standard servicing item? It's a law we're all aware of but, in reality, has it ever been tested in court and how would a judge reasonably look at the responsibility issue?


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## Firestorm (27 Sep 2013)

Longshot said:


> Apologies for the threadjack but this point has always interested me.
> 
> Given that very few people could tell the difference between 30 and say 35 mph by eye whilst driving, how would a driver suspect that his speedo was inaccurate? The answer, I guess, is to ensure that it is tested/calibrated on a regular basis, but how regular would be deemed reasonable in court? Is it a standard servicing item? It's a law we're all aware of but, in reality, has it ever been tested in court and how would a judge reasonably look at the responsibility issue?


Most speedos these days are electronic and dont go out of calibration.


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## CopperCyclist (27 Sep 2013)

I think the 20 mph limits must be legally enforceable as there is a section on the endorsable tickets specifically for "exceeding a 20 mph limit". 

However, that said this question was raised recently at work (not by me) and the given answer s that ACPO (association of chief police officers) guidelines are for police not to enforce 20 limits. This doesn't mean one would necessarily fail if brought to court, but does make it very unlikely to happen.


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## Firestorm (27 Sep 2013)

Obviously , only where the signs are circular with a white background and red edge and are at regular intervals.


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## StuartG (27 Sep 2013)

CopperCyclist said:


> ... the given answer s that ACPO (association of chief police officers) guidelines are for police not to enforce 20 limits.


Which is why the measurable success to date is due to sleeping policemen rather than recalcitrant ones.


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## StuartG (28 Sep 2013)

2678256 said:


> Which is rather sad, as no one likes the sleeping ones.


Yes - I really wish Mr Pickles would stand up for the law abiding road user and remove the need by removing the testicles of random serial speeding offenders and chief constables _pour encourager les autres.*
_
*A more effective deterrence might be considered.


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## dellzeqq (28 Sep 2013)

CopperCyclist said:


> I think the 20 mph limits must be legally enforceable as there is a section on the endorsable tickets specifically for "exceeding a 20 mph limit".
> 
> However, that said this question was raised recently at work (not by me) and the given answer s that ACPO (association of chief police officers) guidelines are for police not to enforce 20 limits. This doesn't mean one would necessarily fail if brought to court, but does make it very unlikely to happen.


that's it in a nutshell. ACPO (which in my experience is an organisation shaking down the suppliers of building supplies for kickbacks) decides which laws matter. It's time to off them.


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