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A new study from Imperial College London finds that speed cameras reduce crashes by 30%

According to a new study from Imperial College London the number of road traffic collisions falls by 30% in areas that feature speed cameras.

The study is the first of its kind in road traffic accident analysis to use a particular type of statistical analysis that takes extra variables into consideration, other than the basic factors of whether an accident happened in a particular location.

The findings come from the Department of Civil Engineering at ICL. A team of scientists from the department took data from 771 camera sites across England, from Sussex and Dorset all the way up to Lancashire and Greater Manchester, alongside a control sample of 4,787 points randomly sampled across the same areas.

>Read more: West Country faces complete fixed speed camera switch off

The method employed by the team led by Proessor Dan Graham was called a Bayesian doubly-robust estimation method, which they say offers "a promising approach for evaluation of transport safety interventions."

The Bayesian method allowed the team to consider not only measure the statistical likelihood of an accident happening in the areas that happened to have cameras, but whether the fact that speed cameras were present had an impact in the accident happening or not.

>Read more: Watch Cardiff cyclist trigger speed camera

The paper concludes that the model the team used could be used more generally to estimate crash factors and their distributions, to better understand how our roads work.

“Our case study results indicate the speed cameras do cause a significant reduction in road traffic accidents, by as much as 30% on average for treated sites," the paper reads.

“This is an important result that could help inform public policy debates on appropriate measures to reduce RTAs.

“The adoption of evidence based approaches by public authorities, based on clear principles of causal inference, could vastly improve their ability to evaluate different courses of action and better understand the consequences of intervention.”

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36 comments

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Grahamd [469 posts] 2 months ago
2 likes

Cameras can't replace police officers, they don't see close passes and don't identify distracted mobile phone users, all they do is slow the traffic in a given area. Slower traffic results in less accidents, who would ever of thought of that?

They are a blunt tool to address the complex issue of how to keep roads flowing whilst safe for all,   a income generating mechanism. http://www.telegraph.co.uk/news/2017/01/03/britains-lucrative-speed-came...

Plough these proceeds directly into road improvements and then I'll be more inclined to listen.

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ktache [525 posts] 2 months ago
18 likes

They only generate income from those who are stupid enough to blatently break the law, as they are set well above the limit for that particular road, where there are websites and satnavs telling them about their placement, when they have been told by big signs that there are speed cameras, where the speed cameras are painted bright yellow and where there are callibration lines painted on the road.

I think there should be more of them.

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shay cycles [384 posts] 2 months ago
15 likes

Any income generated is not generated by the cameras but rather by those who either:

a)  choose to significantly exceed the speed limit in spite of cameras being there or

b) choose to significantly exceed the speed limit whilst not even being sufficiently aware to notice the cameras are there

Either way the income is generated by those ignoring the speed limits. They make a choice and pay the consequence - seems reasonable enough to me.

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FluffyKittenofT... [1582 posts] 2 months ago
11 likes
Grahamd wrote:

Cameras can't replace police officers, they don't see close passes and don't identify distracted mobile phone users, all they do is slow the traffic in a given area. Slower traffic results in less accidents, who would ever of thought of that?

They are a blunt tool to address the complex issue of how to keep roads flowing whilst safe for all,   a income generating mechanism. http://www.telegraph.co.uk/news/2017/01/03/britains-lucrative-speed-came...

Plough these proceeds directly into road improvements and then I'll be more inclined to listen.

But if they raise so much money, why the heck don't income-starved local councils install more of the things? The funds could go into road improvements, but I'd also be happy if it helped fund local services.

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Sub5orange [101 posts] 2 months ago
14 likes

 

Some dual roads, which i avoid  as much as possible but have to cross on my commute with 40 m/h speed limits are used like motorways with people driving at ridiculous speeds. speed cameras would have my vote.

Especially as

 there is no longer a visible police deterrent.

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brixton hatter [3 posts] 2 months ago
7 likes
FluffyKittenofTindalos wrote:
Grahamd wrote:

Cameras can't replace police officers, they don't see close passes and don't identify distracted mobile phone users, all they do is slow the traffic in a given area. Slower traffic results in less accidents, who would ever of thought of that?

They are a blunt tool to address the complex issue of how to keep roads flowing whilst safe for all,   a income generating mechanism. http://www.telegraph.co.uk/news/2017/01/03/britains-lucrative-speed-came...

Plough these proceeds directly into road improvements and then I'll be more inclined to listen.

But if they raise so much money, why the heck don't income-starved local councils install more of the things? The funds could go into road improvements, but I'd also be happy if it helped fund local services.

The fines go to central Government, not the local councils.

If the proceeds were used more intelligently, the money could go directly to reducing danger on the roads. Also, you could say to drivers "every time you get caught breaking the speed limit, your fine builds a metre of cycle lane."  3

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ktache [525 posts] 2 months ago
6 likes

Or rather than a fine, or a ridiculous speed awareness course, how about a ban, say a month for your first speed offence, 3 months for your second, a year for your third?   With car crushing and maybe tagged curfews for those not abiding by the ban?

I understand the French base the fine on income too.

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davel [1242 posts] 2 months ago
7 likes

... as do other countries, especially Finland. £10k+ fines over here, please... https://www.theatlantic.com/business/archive/2015/03/finland-home-of-the...

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brooksby [2235 posts] 2 months ago
5 likes

But I thought that speed cameras were just an eevil money making tool to steal money from the hard-pressed motorists...? You mean they actually serve a real and useful purpose? Why did nobody say this before??

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Al__S [1197 posts] 2 months ago
8 likes

The tech exists to fit vehicles with speed limiters that are accurate to exact locations of speed limit changes, even in dense street networks. TfL are fitting it to the buses they control- it really is good enough to work in London, with tall buildings. It does need an absolutely accurate and up to date map of the limits, of course.

They should, really be rolling it out as requirment for all Black Cabs and Private Hire. They should make it mandatory for vehicles used by any departmnent of Mayor of London/GLA and for the Boroughs. It would seem sensible to make it part of the CLOCS requirements.

With london leading the way, every other local authority should follow suit. Every vehicle that they control or licence in some way should be speed limited.

The tech and the maps should be available publicy. Insurers could give a discount for vehicles fitted.

Obviously, this doesn't deal with all bad driving. It doesn't even deal with all excessive speed, as weather is important, not to mention the idiotic concept of a National Speed Limit that applies to all unrestricted roads. But it would be a good step

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FluffyKittenofT... [1582 posts] 2 months ago
3 likes
brixton hatter wrote:

The fines go to central Government, not the local councils.

Didn't realise that. Always assumed it went to the authority responsible for the road (who, after all, have to pay for the damage done when drivers drive into street furniture). Guess that explains why there are no cameras at the spots round here where they'd clearly raise a lot of money.

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OldMixte [68 posts] 2 months ago
3 likes

In Avon and Somerset the accident rates dropped by 25% when the speed cameras were switched off, but of course never mind the facts.
When you look at the siting of some of them it is obvious they are there to get funds, e.g, On a dual carriageway with massive central barrier, with separate pedestrian paths and no crossings or traffic lights near, and no accident record at that location.
They only catch the non locals, the locals slow down pass the camera and speed up again.
If they really wanted to reduce the accident rates at those spots they need to make sure the drivers know there is a camera, so they can slow down. At one time they were painted yellow and black but I guess the cash declined so now they are just yellow and don’t particularly stand out. It’s no good finings someone after an accident where personal injury is involved, they need to stop the injuries in the first place, but that would need some money spent on engineering effort to solve the problems.

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brooksby [2235 posts] 2 months ago
4 likes
Al__S wrote:

The tech exists to fit vehicles with speed limiters that are accurate to exact locations of speed limit changes, even in dense street networks. TfL are fitting it to the buses they control- it really is good enough to work in London, with tall buildings. It does need an absolutely accurate and up to date map of the limits, of course.

I always think it's quite funny when you see a sign on the back of a (usually) small van, declaring that "This vehicle is limited to 70 mph".  I mean: no vehicle should be travelling faster than that, anyway, so I've always thought it's a pointless declaration.

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brooksby [2235 posts] 2 months ago
5 likes
OldMixte wrote:

In Avon and Somerset the accident rates dropped by 25% when the speed cameras were switched off, but of course never mind the facts. When you look at the siting of some of them it is obvious they are there to get funds, e.g, On a dual carriageway with massive central barrier, with separate pedestrian paths and no crossings or traffic lights near, and no accident record at that location. They only catch the non locals, the locals slow down pass the camera and speed up again. If they really wanted to reduce the accident rates at those spots they need to make sure the drivers know there is a camera, so they can slow down. At one time they were painted yellow and black but I guess the cash declined so now they are just yellow and don’t particularly stand out. It’s no good finings someone after an accident where personal injury is involved, they need to stop the injuries in the first place, but that would need some money spent on engineering effort to solve the problems.

The Bristol Post always publishes where and when the mobile speed cameras are going to be for the next week.   Apparently A&S declare it ahead of time, because they don't want to be seen to be picking on the hard-pressed motorist...

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Christopher TR1 [117 posts] 2 months ago
8 likes

They even warn mororists of camera locations on the radio over here (Hamburg). I reckon that should be illegal & there should be more covert cameras. To the point where motorists are left with no option but to (shock, horror) OBEY THE SPEED LIMIT or receive a hefty fine.

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Stumps [3465 posts] 2 months ago
7 likes

Speed cameras are not the answer, they are displayed on sat navs and signed to let motorists know they are coming up. Motorists slow to the speed limit then accelerate again. 

The answer is average speed cameras. It means over that stretch of road you have to stick to the limit otherwise your knackered. You can have them over a massive distance quite easily which slows everyone down. 

They are also cheaper to install and run than the traditional yellow box speed camera. 

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Al__S [1197 posts] 2 months ago
5 likes

Average speed are good, but only really appicable where you've got a stretch without junctions- in town it's often racing between lights that's an issue, and average speed won't capture that,

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Edgeley [452 posts] 2 months ago
1 like
Al__S wrote:

Average speed are good, but only really appicable where you've got a stretch without junctions- in town it's often racing between lights that's an issue, and average speed won't capture that,

 

Of course average speed cameras would catch people who have sped to get through lights.   Unless they immediately slow right down afterwards to below the speed limit to get the average back down.   In which case, why bother to speed through the lights?

 

 

The secret would be not to have the measurement points too  far apart.

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davel [1242 posts] 2 months ago
2 likes
Edgeley wrote:
Al__S wrote:

Average speed are good, but only really appicable where you've got a stretch without junctions- in town it's often racing between lights that's an issue, and average speed won't capture that,

 

Of course average speed cameras would catch people who have sped to get through lights.   Unless they immediately slow right down afterwards to below the speed limit to get the average back down.   In which case, why bother to speed through the lights?

 

 

The secret would be not to have the measurement points too  far apart.

Racing between lights. Al__S didn't say speeding through lights.

If average 30mph speed checks are half a mile apart, you're expected to cover that half a mile in 1 minute or more.

If you're stopped at lights for say 30 secs, you gain an extra 30 secs to drive like a dick (or increase your average speed by 50% (to 45mph)) and still not get flagged.

A combination of the two (average and absolute) speed checks is needed for adequate coverage and enforcement.

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Yorkshire wallet [1083 posts] 2 months ago
2 likes
Christopher TR1 wrote:

They even warn mororists of camera locations on the radio over here (Hamburg). I reckon that should be illegal & there should be more covert cameras. To the point where motorists are left with no option but to (shock, horror) OBEY THE SPEED LIMIT or receive a hefty fine.

Covert cameras......Speed cameras get put up in what are supposed to be accident black spots. 3 got put up on a road near me after  a couple of deaths and serious accidents within a certain timeframe.  Making them 'covert' does nothing to reduce speed through that area. You don't let someone walk around with a knife until the murder someone and then it's 'your nicked'. Why let someone speed and then punish them?

Anyway, I'm sure in years to come with GPS and car control advancing, there'll probably be no more speeding.

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thereverent [443 posts] 2 months ago
8 likes

I live by one of the roads into London that has had averahe speed cameras on it for a year now (A316). It has made a big differece and makes it more pleasant using that road now.

We need far more average speed cameras as people do obey them far more.

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Al__S [1197 posts] 2 months ago
2 likes
davel wrote:

A combination of the two (average and absolute) speed checks is needed for adequate coverage and enforcement.

Or, as I say, better to limit speeds.

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davel [1242 posts] 2 months ago
4 likes
Al__S wrote:
davel wrote:

A combination of the two (average and absolute) speed checks is needed for adequate coverage and enforcement.

Or, as I say, better to limit speeds.

I think we're a way off that, culturally: we need to get there somehow, but I don't see any of our 'leaders' even willing to broach the subject and risk the wrath of the Clarkson worshippers.

Whereas doubling, tripling the number of cameras? I reckon they could be ramped up fairly stealthily. It's a poor substitute for having an adult national debate, but we can't do that in the UK.

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stonojnr [9 posts] 2 months ago
1 like
thereverent wrote:

I live by one of the roads into London that has had averahe speed cameras on it for a year now (A316). It has made a big differece and makes it more pleasant using that road now.

We need far more average speed cameras as people do obey them far more.

It certainly makes driving on the A14 through Cambridgeshire/Huntingdonshire less fraught,but they fitted some to the Orwell Bridge in Suffolk & dropped the limit to 60mph, its recorded 6000 speeding offences in 6 months,and only now averaging about 500 per month. One driver, who has since been banned was caught 8 times on the same stretch of cameras.

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PaulBox [644 posts] 2 months ago
5 likes
thereverent wrote:

I live by one of the roads into London that has had averahe speed cameras on it for a year now (A316). It has made a big differece and makes it more pleasant using that road now.

We need far more average speed cameras as people do obey them far more.

I've been quite surprised recently by the number of people who either ignore or don't understand average speed cameras. I drove up the M1 last Thursday, hit a section of 50mph avg cameras through a long stretch of road works and stuck my cruise control on, probably at about 53mph as I like to live on the edge. The amount of cars who just cruised past me at 60mph+ was amazing, some were doing more, then slowing for the cameras, I think those ones were in the special class for maths....

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DaveE128 [862 posts] 2 months ago
1 like

Ok, so first, hands up - I haven't read the study, but the description in the article makes me wonder if they have forgotten about regression toward the mean? (See http://www.sciencedirect.com/science/article/pii/S0001457509000979 )

Speed cameras are installed at areas where there have been an abnormally high number of serious accidents right? So you would expect the number of accidents to be lower in the years following than in the year or years leading up to the installation of the cameras. It may have nothing to do with the cameras, just that if you monitor the number of accidents at a location where accidents have randomly "spiked", they will be lower after the "spike" than during it.

Again, I haven't read it, so I don't know whether this is actually an explanation of what they observe.

I am totally in favour of getting rid of humps, chicanes, etc, and replacing with average speed limit cameras. There is a long and heavily used road near me with a 30mph limit and no significant turnings for nearly 900m, and yet when I suggested that an average speed limit camera should be used rather than traffic calming measures, when the council proposed removing chicanes and putting in speed cushions (hello cutting-in motorists!) I received the following total nonsense from the local councillor: "I will take forward the point about an average speed camera but this would be complementary to other measures.  Given the length of this arterial road, we are obliged to have some physical measures in places to reduce traffic speeds." So... long arterial roads oblige highways authorities to put in physical measures to reduce traffic speeds? Humps on the motorway anyone?! 

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GuggeP [1 post] 2 months ago
1 like

I have a little doubt about the accuracy comparing camera spots with random spots on the road without camera. Since cameras are placed primarily on roads that has a history of accidents (at least in my country) you are comparing roads that prior had accidents with random parts of the road. I can not really imagine how that would affect the figures, but I woudn't be so sure that the 30% figure is accurate. Apart from that, interesting article, and I'm sure cameras have some benefits.

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Gourmet Shot [162 posts] 2 months ago
1 like
ktache wrote:

They only generate income from those who are stupid enough to blatently break the law, as they are set well above the limit for that particular road, where there are websites and satnavs telling them about their placement, when they have been told by big signs that there are speed cameras, where the speed cameras are painted bright yellow and where there are callibration lines painted on the road.

I think there should be more of them.

That assumes it isn't a copper hiding in a bush.  Plenty of them where I live usually on stretches of road where pedestrians are non existing but where there's a nice big juicy road that 99% of cars would struggle to keeping below 30mph...it very much smells of gouging the average motorist. 

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ktache [525 posts] 2 months ago
6 likes

If the average motorist is breaking the law with impunity then gouge, gouge and gouge some more.

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Gourmet Shot [162 posts] 2 months ago
0 likes

may as well lock up those Jay walkers as well 

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