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Speed Camera Flashes?

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Martin King 227/12/2021 11:41:52
980 forum posts
436 photos

Hi All,

Coming back from Cornwall yesterday, nice clear almost empty roads and good weather so was bowling along with cruise control set at 77mph.

Gabbing away to the missus so did not notice the speed increase as we went down a long hill but too late saw the grid lines on the road.

Looked in the mirror just in time to see a camera flash JUST ONCE. I had not missed another flash. (84mph!)

I thought they had to flash twice to get you using some sort of DOPPLER?

Or is this just wishful thinking?

Not looking forward to a late Xmas present from Devon Police!

Happy New Year to everyone!


HOWARDT27/12/2021 11:51:17
900 forum posts
39 photos

Don't know the answer to your question, but I noticed on my last trip down there in October along the M5 ect, a number of new cameras that I hadn't seen before. Only became aware of them when a couple of cars got flashed on the M5 going in the opposite direction. The camera I saw seemed bigger than others I had seen so maybe different technology. Speed awareness course may be easier if available option.

Ian P27/12/2021 11:51:30
2578 forum posts
114 photos

If you do get the present it will be well deserveddevil

Speedy Builder527/12/2021 11:52:36
2590 forum posts
207 photos

I went thro one the other month, 1 flash (France). I was travelling at an indicated 94 Kph in what I thought was a 90 limit - It turned out that there was a short section of 70Kph where I missed the signage. My Renault digital speedo reads 94 tor a GPS indicated 90Kph.

The fine arrived 3 weeks later. 70 Kph limit, 85 permissible max speed (which I didn't understand) Fine for 5kph over limit - 1 point and 46€ if paid promptly. French points system starts at 13 and works its way down. For minor offences, points are cleared after 24 months if you are a good boy.

It was a bit of a bugger as a week before the fine arrived, I received a letter saying that the last point (2 years ago) had been erased.

vic newey27/12/2021 11:52:44
148 forum posts
77 photos

Why would you deliberately set the cruise control to break the law?

Tony Pratt 127/12/2021 12:00:01
1926 forum posts
12 photos
Posted by vic newey on 27/12/2021 11:52:44:

Why would you deliberately set the cruise control to break the law?

I'll answer for MK2, it is assumed speedos read 'fast'.winkCruise controls don't slow you down going down hill, well my Focus one doesn't.


Edited By Tony Pratt 1 on 27/12/2021 12:01:48

martin haysom27/12/2021 12:03:49
88 forum posts

the one that got me did not flash at all and like you i was not paying attention. i won't being doing that again [not paying attention that is].

John MC27/12/2021 12:16:04
373 forum posts
44 photos
Posted by vic newey on 27/12/2021 11:52:44:

Why would you deliberately set the cruise control to break the law?

I was wondering the same, presumably because of the "10% +2" rule? (May or may not be a motoring myth).

Seems odd to deliberately set the cruise control (well) over the speed limit unless one knows the accuracy of your cars system, That is to say cars speedo vs actual speed, to squeeze out a few, doubtfully legal extra mph.

My previous car would hold the speed set on the cruise control, using the brakes if it exceeded the set limit by what it considered too much, there was some hysteresis in the system so that the brakes were not constantly on/off.


martin perman27/12/2021 12:18:29
2042 forum posts
86 photos

Most speedo's are set 10% fast but be careful when using your Sat Nav as there is approx 4 second delay between you passing a speed limit sign and your Sat Nav changing to the new speed.

Martin P

mgnbuk27/12/2021 12:19:50
1175 forum posts
71 photos

The two part cameras (seperated camera & flash units - usually covered in yellow reflective panels) mounted singley on the side of gantries on the "Smart" sections of the M62 & M1 around Leeds / Wakefield only appear to flash once when triggered.

I have not triggered one, but fairly often see the cameras on the opposite carriageway flash once - down right dangerous to opposing traffic at night, as the flash is exteremely bright and unexpected. I also experienced one going off in heavy rain at night when another vehicle came past me while a lower speed limit was active on a "Smart" motorway - I assume he got the ticket, as I didn't, but that also stuffed my night vision with the bright flash reflected off the heavy falling rain & wet roads.

Hopefully you will get offered the opportunity to pay for a "Speed Awareness" course rather than an automatic fine & points. Completeing the course should not affect your insurance premiums, but points almost certainly will cause them to increase for 5 years & the increases affect every vehicle you own or are mentioned on the policy of - you can guess how I know this !

Nigel B.

Dave Halford27/12/2021 12:48:16
2004 forum posts
23 photos
Posted by martin perman on 27/12/2021 12:18:29:

Most speedo's are set 10% fast but be careful when using your Sat Nav as there is approx 4 second delay between you passing a speed limit sign and your Sat Nav changing to the new speed.

Martin P

You need to watch that 10% rule. Toyotas read 10% high, which is why you gat flashed by irate drivers assuming you are a speeding maniac while they trundle along at 63. That's also why trucks pass you in 50mph road works zones.

However speedos vary from maker to maker, for ex my Jeep reads spot on speed. Some council run cameras are quite leinent like the French one mentioned earlier, others are spot on. Smart motorway ones are average speed so slow down a lot and you might get away with it.

peak427/12/2021 12:55:15
1671 forum posts
175 photos

This is an excellent forum for engineering queries, but sometimes not the best for legal advice; try Pepipoo for that.

If you saw the flash, and then looked down, there's a good chance that you were actually going a bit faster and automatically took your foot off the loud pedal.

Normally the threshold for prosecution begins at 10% + 2mph, as per the old ACPO guidelines, though some forces use + 3% (i.e. prosecution starts at 79/80 in a 70 zone depending on the police force)
Speed awareness courses are normally offered up to, and including, 10% + 9mph, so you're likely to be offered one if you were actually picked up by the camera, and not an adjacent motorist.

The Admiral group of insurance companies used to increase premiums for SACs, but I think that may no longer be the case.

p.s. don't start worrying about band A-B-C fines etc, as that's only if it gets to court, which this won't unless you want it to.
N.B. dig out the car's V5c (logbook) and make sure the keeper's name and address is correct.
If there is anything coming in the post, you must receive it within 14 days, but even if it's late, the registered keeper still needs to respond with the driver's details within the requisite time period.

Good Luck

Edited By peak4 on 27/12/2021 13:04:55

Pete Rimmer27/12/2021 13:00:59
1219 forum posts
63 photos

Type approval requires that speedometers read between -0/+10% so it will only ever read in your favour as far as complying with the law is concerned but it can be anywhere from bang on to 10% high.

What you do need to be aware of is that many don't apply the error in a linear fashion and in fact some speedos don't even have the digits printed in a linear fashion. For example I drive a VW where the numbers are set out in 10mph segments but after 80mph the scale is halved so the next '10mph' is actually 20. That vehicle reads about 5mph high from 50mph upwards but at 20mph it reads correct. It also over-reads more when heavily loaded I guess because the rolling radius is reduced as the tyres flatten out under the load.

Martin if the camera was one of those on the left gantry post it's unlikely that you got away with it.

SillyOldDuffer27/12/2021 13:07:14
8469 forum posts
1885 photos

Posted by Martin King 2 on 27/12/2021 11:41:52:

... just in time to see a camera flash JUST ONCE. I had not missed another flash. (84mph!)

I thought they had to flash twice to get you using some sort of DOPPLER?

Or is this just wishful thinking?


The speed is measured with radar and doppler shift. The flash is for the camera. The machine photographs the car and number plate for identification, generally twice to ensure a good shot. Best hope is the camera had no film in it!

What happens next depends on how the local force prioritise speeding. Wiltshire used to be red-hot against speeding. Lots of mobile police traps roaming the county, GATSOs galore, and everyone caught was prosecuted. None of this Snowflake Speed Awareness Training either - maximum fines and points. My mate in Frome thought Wiltshire's Chief Constable would have motorists birched if he could! Avon and Somerset were less aggressive, dunno about Devon.


Sam Longley 127/12/2021 13:11:25
939 forum posts
34 photos

I had a speeding ticket when I was 27 years old. It was with a radar gun & it was being demonstrated to a group of about 12 officials. Unfortunately I had never seen one so had no idea what it was. If i had known i would have braked, because I saw it well in advance before the policeman raised it.

I felt so embarrassed that I vowed never to get another speeding ticket. At 74 I have managed so far. When I was working, I averaged 20K miles per annum. With my own business & lots of meetings to get to, many in London, it can be a rush to be on time. The answer is simple. Leave on time.

My current Renault is speed restricted to 70MPH & I quite like that as I can concentrate on driving. I hate the M25 where the speed restrictions vary so much & one has to be on the ball to be sure at what speed one can legally travel. It is easy to miss the signs, if behind a high sided lorry in busy traffic. I can understand how some get caught.

In the country & towns there really is no excuse for speeding. That being said I would still overtake as many as overtook me. Not so much now though, as I really have no need.

noel shelley27/12/2021 13:22:23
1278 forum posts
21 photos

As has been said ALL speedos read high(or spot on ) No manufacturer wants all owners of their models nicked, bad PR ! Noel.

Martin King 227/12/2021 13:31:46
980 forum posts
436 photos

Hi All,

Interesting hat the camera is sited near the bottom of a long straight hill, presumably to catch as many (income producing) drivers as possible. Single yellow camera on a post, not gantry.

Ian P, thanks for that, must be great being a saint! wink

Vic, pretty sure my speedometer (Peugeot digital readout type), reads a bit fast from some timed laps on a private circuit in France. Did it out of interest about 3 years ago at an FOC meeting, (sadly not an owner anymore though!).

Thanks for the info everyone.

Cheers, Martin

Nicholas Farr27/12/2021 13:47:51
3310 forum posts
1524 photos

Hi, while you are normally allowed a grace of 10% over the speed limit, you should not bank on it because going over any speed limit by any amount is breaking the law. Whether you get 1 or 2 mph on top of the 10%, will be subject to the area which enforces the speed limits you are in. Speedometers are rarely accurate and I had a car once that read 10 mph over the speed that I was actually doing and I often wondered why I didn't get a speeding ticket for going passed a few cameras at what I thought I was doing at 76 / 8 mph, it was not until I got my first Sat Nav that I found that my speedo was reading faster than I was going. The Sat Nav I have at the moment reads the speed that I'm doing very accurately with comparison to those non-camera speed checks you often see and it will give me an audible warning and the speed is highlighted in red, as soon as I reach or go over the speed limit that I'm currently in. My current car reads about 2 mph over at 30 mph and about 74 mph over when at 70 mph, so it's not even linear over the range.

Regards Nick.

Nicholas Farr27/12/2021 13:59:25
3310 forum posts
1524 photos
Posted by noel shelley on 27/12/2021 13:22:23:

As has been said ALL speedos read high(or spot on ) No manufacturer wants all owners of their models nicked, bad PR ! Noel.

Hi Noel, but my younger brother once had a car that read 50 mph when he was actually doing 60 mph, he only found that out when a work mate was following him once and asked him the next day why he was in such a hurry to get home as they were in a 50 mph zone, lucky for him, he hadn't passed any speed cameras, but at that time there weren't too many about.

Regards Nick.

Another JohnS27/12/2021 15:00:54
832 forum posts
56 photos

Over here we have active warning signs showing your speed, and consistently shows me being 3 or 4 km/hr faster than what the speedo says.

But you know, cars are about the biggest killers world-wide. People are scared of nuclear plants, planes, and other incredibly safe things, but hop in their car, and "floor it". A combination of kinetic energy, fixed human reaction times and a healthy dose of "I'm better than the other drivers" ego (which we all have) and one has a toxic brew.

Those speed signs? Over here, going 50% faster than the speed limit, when in towns and cities close to schools, etc. seems to be the norm. Yes, people get injured or killed.

Pardon me - got to go and drive to the grocery store, the wife needs some stuff ASAP... :-| John.

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