Do Average speed cameras on the motorways actually work?
A lot of folk travel at 55 indicated reckoning they’re doing around 50 in reality. They’ll then stick another 5 onto that to do 60, reckoning they’ll only be doing 55 and that the cameras will be set to trigger a letter at 60.
AFAIK, they do work. There was an article on the local Beeb website (I’ll try and dig it out) when they added ASCs to the M5 past Brizzle when installing the managed motorway section saying how many thousand drivers had been caught.
In terms of working though, they’re the only thing that have allowed heavier loads of traffic through 50mph roadworks before tailbacks. A darn site better than the Gatsos used previously.Posted 4 years agoscaredypantsSubscriberbikebouyMember
They do work so be careful.Posted 4 years ago
However due to a legal mixup on the M25 ( not the 50mph zone near Clakett Services) but Kent/Surrey area they are not switched on. Something to do with which legal framework has jurisdiction. . They’ve been off for 2 years or so now.
Freely available knowledge that if you want to search for it yourselves.ChubbyBlokeInLycraMember
They do but there is a story that they only work if you’re in the same lane when you pass the second camera as you were when you passed the first. When this circulated up here the cops roundly condemned this type of irresponsible behaviour but never said yes or no to whether this true or not.Posted 4 years agojambalayaSubscriber
@soops I was going to start a thread on exactly the same question !
FYI my GPS shows car speedo under-reads by about 7%, so add a bit of a margin which police/cameras use (ie you don’t get knicked for doing 51 in a 50) and you can be pretty sure you’re safe at 10-12% over the limit, then add in the averaging effect and I think that explains why you have to be going pretty fast to get knicked by the averaging cameras. I believe their primary purpose is to check road tax and insurance, could be wrong about this.Posted 4 years agoernie_lynchMember
Assuming they are completely ineffective against motorbikes? As they are heads up cameras?
On the M25 Kent section they scan both the front plates and the rear plates. I have no idea if it’s enough to clock motorbikes but I wouldn’t risk it. The ordinary traffic cameras would pick up a motorcyclist taking the piss and overtaking everyone, I don’t think it would be very hard to prove that they hadn’t complied with the legal speed limit.Posted 4 years agocrazy-legsSubscriber
The permanent average speed ones on the M60 work, I got done last month doing 60 when it was a 50 limit because I am obviously stupid!
The ones at J25 going clockwise? Yes, they work – a work colleague got done there.
Never sure how much of this is urban myth – all the comments about speedos always over-reading by 10% and you also get people saying that avg spd cameras don’t work if you change lane between camera gantries.
Looking at my speedo vs my sat nav there’s never more than about 4mph between them which is about 5% at 70mph and at lower speeds they’re almost identical – any discrepancy I’ll usually put down to the sat nav being rubbish rather than the speedo.Posted 4 years agoMister PMember
I was surprised on my way to London on Saturday night. The gantry cameras on the north bound lane we happily flashing away at speeders despite there being no temporary speed limit in place. I didn’t think those ones were ever on. I made sure I was under the speed limit on the way home later that night.Posted 4 years agoti_pin_manMember
speedo’s on cars are usually up to 10% out so I’ve read that 10% is allowed. This might help explain why cars come past or go slow in these zones as everybody might think they are doing 50 but everybodies 50 is different. Then there are the knobs who either dont understand the word average or are just knobs.
does naybody think the law to keep drivers left has worked? I see no difference with drivers still overtaking a car a mile away in the middle lane. My pet hate.Posted 4 years agothisisnotaspoonMember
I think the variable speed limit ones must have a larger margin for
error[i]going over the limit[/i] than normal speed cameras.
Going past Birmingham on the M40-M42 I went through the slip roads in a 60, then realised at the last second that the next sign was a 50 so definately went through at a (Sat-Nav) 60.
*I got lucky and the camera didn’t pick me up.
*There’s more than the usual 10% +3mph margin
*They allow you to go through the first sign over the speed limit then slow down for the next gantry
Also what’s the legality of the sign just changing as you go through, presumably there must be a delay between the sign flashing 50 and the cameras being activated, otherwise the first 10 cars would always get caught!Posted 4 years agoFuzzyWuzzyMember
My sat nav reckons I’m doing 50mph when my speedo is reading 55mph, I generally go about 59mph (speedo) through the 50mph M4/M5 zones near Bristol. Pretty sure they don’t kick in until at least 60mph actual though as a couple of times I’ve gone through at least one pair doing over 65mph (indicated) and not received a ticket. And yeah if there are actually people working I’ll drop down to 50mph, for months though the M4/M5 Bristol ones were in a ‘testing & calibration’ mode with all three lanes open and no one working so frankly they can **** off.Posted 4 years agocbmotorsportMember
They also measure your speed between random cameras too don’t they? So between camera 1 and 3 and 2 and 7 for example, so speeding through the first few and slowing right down for the remainder to average 50mph is likely to get you nicked. Also stops people hiding behind lorries.Posted 4 years agobikebouyMember
I did my M25 (south, Kent/Surrey, A3, return) route over the weekend and even in the Clackett Service are roadworks there were cars zipping by me, some I’m sure got clicked and makes me wonder how they will travel next week when they are banned.. 😆
Thanks for the M25 Gantry cameras info, thought the legal issue was still o/s hence the number of “plod cars” sitting on the hard shoulder.
Hey ho.. Better tell my Motorbikermate.Posted 4 years agocr500domSubscriber
The ones that were on the M1 from M25 to Luton for years definitely could not track you switching lanes.
I had a clean license and was travelling up and down here every week at silly hours, so I decided to risk 3 points to see if they worked.
I can safely say, that even enough over the NSL to definitely trigger something, I never got anything through the post.Posted 4 years ago
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