UK speed limits — is there really a “+10% +2 mph” allowance?

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neukStari@reddit

I've been driving like this all my life and have never got a speeding ticket on a motorway.

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Joeb693@reddit

I believe I got flashed on a motorway this morning doing 80 on a 70

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indomitus1@reddit

Lucky. A matter of time if you drive above 80 on a 70

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jake_burger@reddit

You can get a ticket for 71 in a 70 - it’s not likely, but it’s still against the law so be careful.

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I had a man try to break into my house a couple of months back, I phoned the police and they got there whilst he was still kicking the door down.
They told me to allow it and that he was just a bit of a head case and let him walk away.

Fuck the law and fuck the police.

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schmerg-uk@reddit

Worth saying that when one's speedo reads 80, the true speed is typically more like 73 or 74 (as measured by GPS on a phone which is more accurate than counting wheel rotations and allowing for tyre pressure effects etc).

Car speedos are only required to be 10% accurate and manufacturers will normally try to make them accurate, but will err showing a higher speed rather than a lower speed to avoid irate customers blaming them for speeding fines

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JeffSergeant@reddit

That can be a matter of good observation skills rather than the law!

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neukStari@reddit

Yes I generally tend to be somewhat aware of my surroundings when driving, supposedly.

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SmegB@reddit

Same here. I got my first and so-far only ticket last year. My fault tho, ignored the 60 sign and went through a camera at 75

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pineapplepollyps@reddit

Police officer here. It's still an offence to go 1mph over the speed limit technically.

Speed cameras and speed camera vans usually give tickets at around +4-5mph in my experience.

Hand held speed guns are down to the officer. We usually agree to stop anyone going 5mph for words of advice and anything over +10mph is a ticket.

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Forever_a_Kumquat@reddit

I got a ticket for 32 in a 30 from a handheld.

Shame it wasn't you holding it.

Yes I was speeding.. I know.

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Icy-Contest-7702@reddit

What happened when you appealed?

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Forever_a_Kumquat@reddit

Why would I appeal? I was speeding.

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arfski@reddit

There isn't an appeal for I was only breaking the law a little bit, only mitigation, it's quite binary.

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Icy-Contest-7702@reddit

You appeal the calibration of the camera. Thats why the 10% + 2 exists.

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arfski@reddit

Not really, the National Police Chiefs' Councils guidance is just that, it has no legal basis and does not have to be followed.

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Icy-Contest-7702@reddit

Take it this is on slow roads. No chance people are getting pulled over for 75 on a motorway

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Flat_Development6659@reddit

It doesn't have to be stuck to, you can be taken to court for going 31 in a 30.

Multiple forces have confirmed that they suggest a similar rule though.

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spik0rwill@reddit

Taken to court? I very much doubt that. First they make you take a speed awareness course if you havent done one in the previous 3 years. For a second offense you get a fine and points and for the 3rd offense in 3 years you get a fixed penalty notice.

You would only go to court if you do i dunno lets say 50 in a 30, if have accumulated 12 points in 3 years and there's 1 more scenario i can't remember.. I did some research on it a couple of years ago..

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Flat_Development6659@reddit

Taken to court? I very much doubt that. First they make you take a speed awareness course if you havent done one in the previous 3 years

Nah, it's a bit more complicated than that. Police forces don't have to offer speed awareness courses and they don't have to offer a FPN, they can technically take you to court for going 31 in a 30.

For a second offense you get a fine and points and for the 3rd offense in 3 years you get a fixed penalty notice.

Your second offence description is quite literally a FPN, a FPN is you accepting a decision without going to court (E.g. £100 fine + 3 points). If you go to court the fines are based on income and usually work out at significantly more. There's literally no difference between second offence, third offence or fourth offence.

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spik0rwill@reddit

Ok, technically you could, but the likelihood of it happening is virtually zero. The police would have to prove that none of the equipment was faulty, why would they put that much effort in for 1mph. Prosecutors simply wouldn't see it as a good use of taxpayers money, especially when taking into account judge and lawyer costs.

I could see a court appearance happening if the driver that ignored an fpn or was contesting the fine. Again, for 1mph over the limit i find that scenario very unlikely. Yes, i know that offense 2 and 3 are the same. However, you could lose your license for a 4th offense if you hit the 12 point limit and your first offense wasn't a speed awareness course.

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Dannypan@reddit

This tolerance, not allowance, exists because speedometers aren't perfect. Your car might say 30mph but really it's doing 32mph. It's to account for this and human error.

You're still breaking the law by going over the limit. It's a limit, not a target.

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jake_burger@reddit

Speed limits are targets you will fail a driving test for going 20 in a 30 for no reason

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Saw_Boss@reddit

The speed limit is not a target. It's literally just a limit.

If you drive over cautiously, then you will be failed. But you should drive as per the conditions without exceeding the limit.

I drive quite a few country roads with national speed limits, but you'd be a fucking idiot to be aiming for 60mph down the majority of them, with blind sections, poor road surfaces etc.

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jake_burger@reddit

The old country roads excuse.

Yes you should drive to conditions, which is why I said:

for no reason

If you aren’t allowed to hesitate unless conditions dictate it - then the limit is a target isn’t it? Because unless there is reason you should be trying to reach it.

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Saw_Boss@reddit

The old country roads excuse.

Yes, the huge network of these roads across the country.

The point is, it's not a target. It's never been a target. The RAC in fact criticized people who called it a target.

You drive at a sensible speed, not exceeding the speed limit. That's all. It is not and has never been a target.

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Beartato4772@reddit

This isn't true, it's illegal for speedos to suggest you're going slower than you are, which is why they generally read slightly OVER.

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Hulkenberk@reddit

Other way round, it'll more than likely show you that you're at 32mph when you're really at 30mph. If a speedo is showing a lower speed than you're actually travelling at your car needs to go back to the dealer ASAP.

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VictoryAppropriate68@reddit

I was doing 82 in a 70 in my first year of driving and was slapped with a driver awareness course, I was told at the time ‘1mph over and you’ve of had to take points’ which makes no sense at 82 is over the 10% tolerance they talk about.

Basically anything over the limit, even 1mph, is illegal and living your life by the 10% rule will likely bite you in the ass at some point

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DaveBeBad@reddit

Your car speedo generally reads high - typically by 3-5%, but up to 10%.

So while your speedo reads 50, you’re probably doing 46-48. Your GPS would be more accurate.

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Virtuous-Patience@reddit

Speedos are afaik set to be accurate on new tyres, they read faster as the tyres wear and the circumference is reduced meaning one revolution of the wheel does not take you as far as the speedo thinks. So when you have your tyres changed don’t assume it’s still reading slower and giving you the same margin of error.

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terryjuicelawson@reddit

I follow my GPS even with new tyres, it is consistently over. I am generally going past people constantly on average speed camera 50mph limits and have never had an issue.

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DaveBeBad@reddit

Speedos are set to read slightly faster even on new tyres - so you don’t get fined for something that isn’t your fault (if the car says you’re doing 48, when in reality you’re doing 55, it’s a problem)

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theevildjinn@reddit

Your GPS would be more accurate

I've seen this before, but never found a reliable source for it. Does it mean the GPS in a dedicated satnav unit, or is the one in your phone just as good? Of the ones in phones, are the GPU chips all as accurate as one another between different manufacturers and models? Do different navigation apps give the same current speed, using the same data to calculate it?

Anecdotally, I've gone through speed traps many times with my car speedometer above the speed limit and Waze at the speed limit, and not had a ticket.

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DaveBeBad@reddit

Tbh, when I’ve measured speed with a GPS it has been weather dependent. I was once recorded running at 600mph in the middle of the North Sea (it was nearer 5mph in the middle of Rotherham!) - but that was a blustery day…

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theevildjinn@reddit

Yeah that'd make sense to me. When I go to send my current location to someone on WhatsApp, it starts out saying "accurate to x metres", where x might be a few hundred metres if I'm in a location with lots of tall buildings. And then it gradually improves as it gets a better lock on you. I imagine that'd be more difficult in a moving vehicle, in poor weather.

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marvellcg@reddit

Been done for doing 32 in a 30 by a fixed camera. So can confirm that not all speed cameras are set with that as a tolerance.

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gazchap@reddit

The idea of the 10% + 2 is to account for vehicle speedometers overreading, so to be ticketed for 32 in a 30, your speedo was likely reading 35 at minimum (which is 10% + 2)

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marvellcg@reddit

Speedo was reading 33, I know because I looked when I saw the flash.

I was annoyed but ultimately I was speeding so can't complain, I took the driver awareness course so didn't get any points.

Wasn't complaining about it, but a few people had commented that cameras were usually set with the 10% +3 tolerance and I was letting them know that's not always the case.

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Hazz3r@reddit

UK and EU regulation stipulates that Accelerometers must never show a speed that is lower than what the vehicle is actually travelling at.

As a result, the Accelerometer is allowed to over-read by a certain amount.

The speed indicated shall not be less than the true speed of the vehicle. At the test speeds specified in paragraph 5.3.5. above, there shall be the following relationship between the speed displayed (V1) and the true speed (V2). 0 ≤ (V1 - V2) ≤ 0.1 V2 + 4 km/h

If you can't quite read the equation, it essentially says that the max difference between the indicated speed and the true speed can be up to 10% + 2mph.

As a result, for most cars travelling at motorway speed, if your Speed says 70 mph, it's more likely your true speed is somewhere between 64-68.

So without considering the police at all, depending on your car, you can travel at indicated speeds above the speed limit up to a certain extent.

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gazchap@reddit

*speedometer, an accelerometer would give a very different reading!

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Hazz3r@reddit

You're so right!

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WiseMudskipper@reddit

67 mph?!?

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AdPale1469@reddit

no of course not.

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Gildor12@reddit

No, it is totally up to the particular police force. Humberside police are notorious for not allowing leeway. Had to do my speed awareness course for 78 in a 70.

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UnCommonSense99@reddit

Some advice.

If you can't see a big yellow speed camera how the heck do you think you're going to see a clueless pedestrian walking from behind that parked SUV? If your observation skills are this poor its definitely sensible to drive well below the speed limit.

Similarly if you're driving like an arse on the motorway the police will pull you, whereas breaking the limit while keeping distance and using indicators attracts far less attention. Bad motorway drivers are clearly visible because their brake lights keep going on and off. If you plan ahead and keep your distance you rarely use your brakes.

If you do fail to see a speed camera then it's very much the luck of the draw. Some cameras are generous, others are set slightly above the limit on downhill sections... I know people who have been done for 32mph in a 30 in Bristol.

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Forgetful8nine@reddit

It's guidance not an allowance.

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MrMonkeyman79@reddit

Legally there is no tolerance, if youre caught going 1 mph over the speed limit then they can do you for speeding.

From a practical point of view forces often use a little discretion, but I dont think there's a universal formula, and if you don't want a ticket then stick to the limit.

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RecentTwo544@reddit

Depends. For anything automated, normally no. There's some variance but often they're more relying on your speedo over-reading slightly.

Case in point, I got caught by cameras doing bang on 80mph on the M1 (at 3am with no traffic in good weather) and my speedo was reading 80mph, so I assumed I was doing \~77mph and this logic might apply. Bang to rights, speed awareness course, I didn't deny I was speeding or that it was fine/safe, but after a few more tests I've realised my speedo does, unusually, give an accurate reading of my actual speed.

Actual coppers might be a bit more lenient provided you're not being wanton with it. I've been told some police forces have guidelines along the lines of the "10% +2" but it's largely officer discretion. Doing 35mph in a built up area during school kicking out time and they are more likely to pull you and issue a speeding ticket than if you're doing 80mph on a quiet motorway, where they are very unlikely to go to the effort of pulling you off at the next junction.

I've twice (in my younger years) been pulled for drifting into a 30mph zone still doing 40mph. Very late at night, totally dead roads. The latter time was actually because I was concentrating so hard on the marked police car behind me I missed the 30 signs! 40 in a 30 is quite significant, 33% over the limit. But I was polite, held my hands up, admitted I was bang to rights, had a polite chat and a laugh with the copper (the latter was a sergeant too) and they let me off with a "it wasn't excessive, and it's late, we're all trying to get home, just please be careful in future."

Jury's out to which is the better approach - automated or human.

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Doobreh@reddit

What did it say on the NIP, 80? Then your speedo is bang on. if you want to be sure, install waze and see what speed it gives you.

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RecentTwo544@reddit

Yep, 80mph. Waze, a few other GPS speed devices, and those SID things you see by the side of the road that show your speed, all tracked the same.

Mentioned it when I had the car serviced and they said it just happens sometimes.

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Doobreh@reddit

What brand car is it? I've had two Mercs in my time and they were always bang on. Every other car read high to varying degrees.

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RecentTwo544@reddit

VW Golf.

I did smack the left front wheel on some steel trackway at a festival so was worried it might have sent something out of kilter, but after a wheel alignment it was still the same.

Maybe it's a German thing.

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sheepandlambs@reddit

As someone who did the speed awareness course last year, they stressed that even 1mph over the limit can be a huge issue with stopping distance.

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treadtyred@reddit

Also your Speedo will be set to read over by a few mph.

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RonsonGlitter@reddit

I've found that to be the case, yes. It's not "official" but does seem to be a de facto reality.

I've been happily sailing through speed cameras & past police at +10% for decades, no tickets. But I have had tickets for going much beyond that. Also I do slow down for actual plod. They can f*ck you any time they like, e.g. if chummy is taking the piss for one thing they can easily get you on another.

I would settle for just the 10%. If you push into the extra little bit of leeway you're entering the risk zone, for hardly any gain. So 33/ 44/ 55/ 77.

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Beartato4772@reddit

A police officer with a properly calibrated detection device can stop you for 61 in a 60 and you will have no defence.

However, cameras are generally set to 10%+2 or 3 mph yes. In practice unless you're driving dangerously a police officer will tend to use the same discretion.

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iffyClyro@reddit

As a general rule, yes 10% +2 or +4 depending on the equipment is an accepted standard, this relates to the issuing of tickets.

However if you receive a ticket for 75mph in a 70mph zone you can’t use “but the 10% +” as a defence.

Source: Police Officer.

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Rivyan@reddit

Did 65 on a dynamic speed limit motorway when it changed from 70 to 60 and I was still slowing down with engine brake. Got a nice fat ticket a few weeks later.

I ain't fucking around since then. Sign says 70, I am doing spot on 70. Only driver with 2 kids and a wife, can't risk putting points on the license or we are fucked.

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Doobreh@reddit

10%+2 is the enforcement point. So 10% + 1 you should be fine. ie 23 yes, 24 no, 34 yes, 35 no, 78 yes, 79 no. Though if anyone is going to enforce lower it will be at the 20 or 30 speed limits.

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Gone_For_Lunch@reddit

Officially anything 1mph over is speeding. The “+10% +2mph” is camera tolerances and guidance for prosecution.

Ultimately, it’s going to depend on a number of factors.

Driving at 77mph on a mostly clear motorway? Probably safe.

Driving 35mph in a built up zone with a lot of people around? Probably not great.

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Jlaw118@reddit

No there is not. And I learnt this the hard way getting picked up doing 46 in a 40 by a mobile camera.

I think a lot of the fixed cameras have a tolerance, but I wouldn’t like to risk it.

Technically 1mph over is speeding and you could be prosecuted for it but it depends on the police force in the area at the time.

Your vehicle, unless a truck calibrated for tachograph, is usually a few mph out anyway which tends to inflate. Try a motorway run using Google Maps/Waze and take that speed limit for gospel as it’s more accurate than your car’s speedo.

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blondererer@reddit

I’m not encouraging speeding- my county do follow this. As an example, on a 30mph road, they offer speed awareness at 35mph. I believe speed awareness stops being offered at 45mph.

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spectrumero@reddit

In law - no there isn't. If the limit is 60, then 61 is speeding and you can be successfully prosecuted for doing 61 in a 60. However, police forces often apply som leniency on the level they will prosecute you at.

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theloniousmick@reddit

I'm sure someone more knowledgeable will give a definite answer but I think I remember reading it's an urban myth and you can get done for being 1mph over the limit. I remember hearing the 10%+2 was to account for variation in speedometers/ camera calibration, but dont think it holds up in court.

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geeksandlies@reddit

There was an article recently where it is basically force dependant, not all will have the same buffer and none will disclose what their buffer is, my advice is to lift through cameras to the limit and don't mess about with average zones. I have received two tickets in 20+ years of driving, one for a roadside van that caught me as I was overtaking and the other was because I FAFO in Wales years ago, 66 in a 60 as the limit lowered coming off the Severn Bridge on the M4.

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slimboyslim9@reddit

I did a speed awareness course a couple of years ago, it was actually really helpful and educational, being 20 years removed from learning to drive originally. You are breaking the law even 1mph over the limit but the police are highly unlikely to prosecute until you get to the 10% +2 level because you could claim the equipment wasn’t accurate.

Of course, you should also consider when doing 57 in a 50, and 79 in a 70, that if your equipment indeed isn’t accurate, you might actually be doing 60 in a 50 or 85 in a 70 and then you’re very likely to get a ticket. I now allow myself about 5-8% flexibility.

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D34TH2@reddit

I haven't had any experience of being stopped or getting a ticket from speed, but I would assume that the 10%+2 is based on your cars speedo rather than any more accurate measurements.

It is also probably only for fixed single point cameras due to limitations of the hardware. Average speed zones are likely to be more accurate.

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TobsterVictorSierra@reddit

It's the old ACPO guideline. The ACPO no longer exists. Most (but not all) police forces still use this guideline for unmanned or civilian manned enforcement devices. For most police forces you can find out what thresholds they use on their website, either as general information or FOI publications.

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Lunaspoona@reddit

Depends on the local force. I think they have it somewhere on their website.

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sunflowersunset1@reddit

Well I once got a speeding ticket for doing 60 in an average speed check zone (my fault completely). But on the letter I received with the ticket it had the prosecution speeds for each limit and I remember it said that they prosecute above 59 in a 50! Not sure if that’s because it’s average speed check and obviously if you take racing corners you could theoretically take less time to go the whole road. But I assumed it means that there is at least some leeway when speeding.

Did my speed awareness course and have never had another ticket though 🥲

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Own-Lecture251@reddit

If I remember right the “10% + 2 mph” is/was a recommendation by the College of Chief Police Officers (whatever it's called) but it's never been the law so you can, in theory, get a ticket for doing 61 in a 60. I think they do allow some tolerance because speedos aren't accurate although they read high rather than low by 2-3mph.

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sammy_zammy@reddit

Speed cameras are usually set at that, yes. However it’s still illegal to go 1mph over the speed limit, and you still could be pulled over for doing so.

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