M4 / M5 Gatsos are now live - beware!

M4 / M5 Gatsos are now live - beware!

Author
Discussion

fatboy69

9,372 posts

187 months

Wednesday 4th June 2014
quotequote all
silverback mike said:
Folks,

They are all live on the motorway now, and shortly all the rural ones will be being made live also. grumpy
bds.......

McAndy

12,446 posts

177 months

Thursday 5th June 2014
quotequote all
silverback mike said:
Folks,

They are all live on the motorway now, and shortly all the rural ones will be being made live also. grumpy
Rural ones?

silverback mike

11,290 posts

253 months

Thursday 5th June 2014
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Alledgedly all cameras that have been switched off, both motorway and non motorway are being re-activated to become live again.

Not too sure on timings, but that's apparently the plan....

BristolRich

545 posts

133 months

Friday 18th July 2014
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1502 caught in 14 days...

http://www.bbc.co.uk/news/uk-england-bristol-28329...

[cynical mode]
Why is it every time I’ve done the M4 to M5 drag Friday, Saturday and Sunday, midday, morning or late eve are the Matrices on set for 60? 60 appears to be the default with an odd 40 thrown in to keep you on your toes.

In "most" cases the road was no busier than a normal day where traffic does not require "management". Granted its going to be bad when the kids break up but they seem to be permanently on over weekends.

[/cynical mode]


TDIfurby

1,997 posts

175 months

Friday 18th July 2014
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I've only seen it at 60 at fairly peak times. Having said that, it's not my regular commute so can't comment based on a lot of observations. smile

DevonPaul

1,183 posts

137 months

Friday 18th July 2014
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I've only been that far Oop North thrice since they went on, one evening trip and an early Friday afternoon one, when they weren't lit at all, and a wet Weds rush hour when they were at (IIRC) 50 and traffic was actually moving OK much to my surprise.

From the figures, about 90% were offered a Speed Awareness course, 10% FPN, and about 1% got a summons. For the latter thay must have been doing 30mph or so over the posted limit, despite the signs, so really there's little hope for them. From my understanding there is a delay between the limit dropping and the camera becoming active at the lower limit, which is kind of reasonable.

Perhaps they left them inactive for ages just to lull people into a false sense of security wink

runcoach 100

1 posts

114 months

Tuesday 7th October 2014
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I can confirm that the Gantry Cameras on the M5 Southbound around the Cribbs Causeway area are active and they are issuing tickets. Received one today, offering speed awareness school for doing 81 mph in a 70mph limit. There were no active limits displayed on the gantries so this is a straightforward ticket for exceeding the national speed limit. Beware if you are passing the area. It was night time so I cannot recall which particular gantry set flashed me but it was in the section between the m4 junction with the M5 and the cribbs causeway area heading southbound on the M5

TDIfurby

1,997 posts

175 months

Tuesday 7th October 2014
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Dad got done also on M4 stretch - doing 85! I tried telling him before those cameras are still NSL cameras even when "off" in quiet times of day.

wessexrfc

4,326 posts

186 months

Wednesday 8th October 2014
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Coming back passed Bristol late last night, two went off on the North bound over head gantries.

dazren

22,612 posts

261 months

Thursday 27th November 2014
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These are currently issuing notices for 57 in a 50.

RemaL

24,973 posts

234 months

Thursday 27th November 2014
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dazren said:
These are currently issuing notices for 57 in a 50.


So the person doing 57 would be doing more like 59-60MPH unless they are driving using a GPS?

dazren

22,612 posts

261 months

Thursday 27th November 2014
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Speedo accuracy varies from car to car, you'd need to do your own tests. I'm just pointing out people are getting notices for 57 in a 50. ie they aren't giving much of a buffer. It's my understanding that at the time conditions were good, minimal traffic, no queues to get off the motorway etc.

LordBretSinclair

4,288 posts

177 months

Thursday 27th November 2014
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Standard ACPO guidance - 10% plus 2 mph frown

Wing Commander

2,180 posts

232 months

Wednesday 3rd December 2014
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Got flashed going North on the M5 just about to turn off onto the M4.

As per previous posts, it was 60 60 60 60 etc and then a quick single 40 right at the end and I was too busy merging and driving etc. Still my fault, of course, but pretty pointless as I was slowing down and looking at my speedo showed just under 50 I think and I was already on the brakes. Ho hum, let's see if I get my government issued christmas present of a picture of my car.

I don't know the ins and outs of the tech behind the Gatsos. As I understand it, the radar is monitoring the speed of the car. If it hits the trigger, it fires off the two flashes with the corresponding photos. Is it the calculation done by the photos or the radar itself that determines if I was speeding? In theory, if the trigger was 46mph and I was doing 46.1mph, as determined by the radar, then I am done. But if I am already slowing, and I was doing 46.1mph at the first photo and 42mph at the second, then my average would be lower than the threshold for being caught - see what I mean? Anyone have any ideas???

LordBretSinclair

4,288 posts

177 months

Wednesday 3rd December 2014
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They flash at half second intervals and apart from taking your registration number they are used to corroborate your speed with the secondary markings on the carriageway.

With only a half a second difference you will not have enough time to react and brake and reduce your speed at all. If you got flashed you're likely to get done frown

Wing Commander

2,180 posts

232 months

Wednesday 3rd December 2014
quotequote all
LordBretSinclair said:
They flash at half second intervals and apart from taking your registration number they are used to corroborate your speed with the secondary markings on the carriageway.

With only a half a second difference you will not have enough time to react and brake and reduce your speed at all. If you got flashed you're likely to get done frown
Normally I would agree with you but I was already on the brakes anyway, so there will be certain amount of truth to what I suggest. Obviously, if I get caught, I get caught and so be it - my fault entirely, but just trying to work out methodically how they work.

Does the ticket come from the radar calculation or the two photos calculation? Impression I get is that the radar does the speed calc, one of the photos then gives the reg, and the two photos calculation is brought out to verify things if required. But I dont know this for certain, hence the question smile

giltranator

347 posts

188 months

Wednesday 3rd December 2014
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I've moved offices to Aztec West and I can't believe the way they are using the gantries...

Monday morning, All of the gantries set to 60 apart from one gantry which showed 40 and then the next one was 60. Trust the one that was 40 to be the one with cameras on!!! (not all of them have cameras, if you look underneath the matrix sign you will see the camera - square box). I saw 4 people get flashed by that camera in the space of 20 seconds!

LordBretSinclair

4,288 posts

177 months

Wednesday 3rd December 2014
quotequote all
Wing Commander said:
Impression I get is that the radar does the speed calc, one of the photos then gives the reg, and the two photos calculation is brought out to verify things if required.
In a nutshell yes, by the time the camera flash goes off for the first time the speed reading has already been taken - good luck smile

BFG TERRANO

2,172 posts

148 months

Wednesday 3rd December 2014
quotequote all
Wing Commander said:
Got flashed going North on the M5 just about to turn off onto the M4.

As per previous posts, it was 60 60 60 60 etc and then a quick single 40 right at the end and I was too busy merging and driving etc. Still my fault, of course, but pretty pointless as I was slowing down and looking at my speedo showed just under 50 I think and I was already on the brakes. Ho hum, let's see if I get my government issued christmas present of a picture of my car.

I don't know the ins and outs of the tech behind the Gatsos. As I understand it, the radar is monitoring the speed of the car. If it hits the trigger, it fires off the two flashes with the corresponding photos. Is it the calculation done by the photos or the radar itself that determines if I was speeding? In theory, if the trigger was 46mph and I was doing 46.1mph, as determined by the radar, then I am done. But if I am already slowing, and I was doing 46.1mph at the first photo and 42mph at the second, then my average would be lower than the threshold for being caught - see what I mean? Anyone have any ideas???
I got flashed there doing about 45 or so. It was about 3 weeks ago and so far nothing through. I understand it takes two photos and they count how many white dashes you pass between photos to determine speed.

Wing Commander

2,180 posts

232 months

Thursday 4th December 2014
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Thanks guys, as assumed I will just have to wait and see! Thanks!