Average Speed Cameras.

GeorgeMcFarlane

Hi guys I'm a newbie on here and need some advice on how these average speed cameras work, and wether or not i need to start worrying.

I was travelling along the M74 in Hamilton on Saturday in the 50mph average speed zone when a oldish driver moved over into my lane, I indicated to move over into the middle lane to get past and noticed that I was doing 59/60 on the speedo but 55 on the sat nav. I immediately slowed down to 40 until I was passed the next camera at the Motherwell cut off. I was doin 59/60 for only a matter of seconds. Will this still calculate my speed at 50 or have I been down for excesses speed. I've looked all over the net and someone said that if I was doing say 60 and slowed to 40 I add these together to give me 100 the divide it by 2 = 50 and that would give me the 50.

As I say Im a newish driver and can't Work out how these work


Thanks in advance

dannyrst

Each camera records the time you pass through. After the first one, each camera will determine your speed from the duration it took you to go the distance between the cameras. If you average (just over) 50mph, you are fine.

Aylesbury_Duck

The only way you can properly work it out is to take the distance between the camera points and divide it by the time it took you to travel between them.

e.g. say there is one mile between camera points. Suppose you take one minute to cover that distance. You have covered one mile in one minute which equates to an average speed of 60 miles per hour. For the sake of calculation, it doesn't matter how your speed varied at points in that minute. You may have even stopped briefly. Your average speed between the two points is 60 mph.

It sounds like you're okay if you were doing 55mph true speed for seconds and 40mph for the majority of the measured distance.

GeorgeMcFarlane

Would u say the sat nav is more accurate than tha car speedo. As I say I'm a newish driver and can't get my head round it all.

spadoosh

GeorgeMcFarlane wrote: »

Would u say the sat nav is more accurate than tha car speedo. As I say I'm a newish driver and can't get my head round it all.

In theory sat nav should be more accurate, in reality it isnt. I dont know if you've played pokemon go but my little dude wonders around while im sat still, that uses GPS. Your speedo tends to go off rotation of axle or wheel. So if for example you compare a flatter and more inflated wheel the rotation would be different. So neither are 100% accurate and youll struggle to know which is more accurate without measuring them properly.

I wouldn't worry about it, youll either get a speeding ticket or you wont. No amount of worry will effect that. What your worry can effect is your driving going forward, use that to your advantage so you dont have to worry about it again (ie make sure youre not speeding if youre going to worry about being caught!)

daveyjp

Average speed cameras are now often coupled with an instantaneous camera for those who decide that once they have passed the last camera they can boot it.

All the OP can do is wait, but I suspect on that recollection there is nothing to worry about.

bod1467

OP ... I know this stretch very well. From what you've described you'll be fine.

rhysadams

Its a horrible feeling isn't it, I tend to set my speed limiter at 55mph but if I press my accelerator harder it can go passed this point.

I have known people to get tickets in between cameras and they reckon that they were only speeding for a split second, however not sure if I believe them or not.

There are some good guides to types of speed cameras on the internet

bod1467

I have done before exactly what OP describes, in that exact stretch of road. I have not received any notification.

I usually have my cruise control set to 54 (indicated 50 on the satnav), and I regularly get people overtaking me. If they were getting "nicked" by the cameras I doubt there'd be so many people doing it.

OP - as I said before, you'll be fine.

SpekySquarehead

FYI.

My good friend is a taxi driver and he had a passenger who put up the average speed cameras on the M8 in Lanarkshire and he said the they hadn't been calibrated and you could speed through them (which was a rumour in the local area anyway). So doing the nightshift one night he went for it and instead of the 50 he drove at 60. Few weeks later the police come to the door saying he ignored his original speeding letter (which he never got). Anyway, I'll get to the point. It went to course and his lawyer said that the speed cameras were too high and so the high winds may have knocked them off slightly and so cannot be guaranteed to give an accurate result. He was let off.

This may be a unique case though but just bear in mind should anyone get caught.

Mercdriver

SpekySquarehead wrote: »

FYI.

My good friend is a taxi driver and he had a passenger who put up the average speed cameras on the M8 in Lanarkshire and he said the they hadn't been calibrated and you could speed through them (which was a rumour in the local area anyway). So doing the nightshift one night he went for it and instead of the 50 he drove at 60. Few weeks later the police come to the door saying he ignored his original speeding letter (which he never got). Anyway, I'll get to the point. It went to course and his lawyer said that the speed cameras were too high and so the high winds may have knocked them off slightly and so cannot be guaranteed to give an accurate result. He was let off.

This may be a unique case though but just bear in mind should anyone get caught.

At the risk of losing £1000+ in court costs fines etc, do you mind if we allow you to test the waters on that one? Thanks.

In all seriousness, it's not helpful to spread rumours from 'down the pub' as pretty much every loophole has been closed and it's an expensive day in court if you decide to rely on Joe Bloggs down the Nag's Head.