Hi, I have a question about average speed cameras. I was driving from Leicester to Colne in Lancashire today and I went through some roadworks on the M60 (I think it was the M60). Any way I was very good... As soon as I entered the roadworks (50mph limit) I placed the car in cruise control on 49/50. I drove through the long roadworks, passing average speed camera after average speed camera. On coming to the end of the roadworks I saw the national speed limit signs a hundred or so metres ahead of me and began to increase speed in anticipation. However, I didn't notice a final average speed camera placed just before the national speed limit sign until shortly before. When I saw it I instantly slowed down. In short I think my speed reached 58 mph for a few seconds before I braked and it was down to about 54 mph as I passed it (but there really were only a few metres left before the national speed sign). I'm not sure how these average speed cameras work. So will I get done?

Thanks for your help.

Highly unlikely.
Although there is speculation about what speed is "booking speed" for average speed cameras, consider that your speedo probably over-reads so you it's likely you were averaging closer to 45 than 50. A final burst at an indicated 60-ish (probably 55 in reality) would never get you close to exceeding the speed limit for the whole stretch.

m66 at a guess

think youl be safe, due as much to the fact you speedo was prob reading fast any way and the guidance for prosecution is 10% plus 2 mph ie 57 averaged over the distance from the last camera

Average cameras calculate average speed over a set distance. Your speedo is probably 2 mph or so fast. In the circumstances described it would be amazing if your average was over 50mph and even then i doubt the cameras are set bang on or they wouldn't cope with the paperwork.

It makes little difference overall, particularly in long stretches, if you pass 1 camera a bit quick if you observed the speed limit for the most part.

Average camera not a fixed camera. If anybody happens to be reading that travels the A80 please stop braking at the cameras or i might just give you a slap for stupidity. Thanks.

Cheers

Cheers Catweazle. So is there are margin of error/discretion with average speed cams? I mean I've heard of the 10% rule (although I don't know whether it's true) with regard to normal cams. So if your average speed was, say 54, in a 50 zone (not that mine was, as I really only sped up for a few seconds before slowing down - and that just before the final camera) will they send a ticket?

I don't think we know, Jules. Someone on here speculated that the threshold for prosecution for average speed cameras is lower than + 10% +2, but all the actual cases reported have been way above that figure.
When I can, I usually drive through 50mph average speed areas at an indicated 57mph (53mph according to sat nav) and haven't had a ticket.
(Daft thing to say - there'll probably be one on the mat tomorrow )

Thanks for the answers chaps. I can rest easy now. Getting a ticket for the first time earlier in the year through a genuine mistake has made me extremely nervous about speed cams so now I drive exclusively with cruise control set at 70 on Motorways now - or whatever the controlled speed is. I'm obviously over-reacting but getting caught by a speed cam has made me paranoid about my speed.