How accurate are average speed cameras

Kimbot

https://www.boards.ie/discussion/comment/121456518#Comment_121456518

If your speedo is out then get the garage to write some form of letter to help with your appeal if possible.

https://www.boards.ie/discussion/comment/121456535#Comment_121456535

I will ask for sure.

Nothing ventured !

Miscreant

@Skyrimaddict Are you sure your car has it's original wheels? What make and model is it? I know you said in an earlier post that you have 18in wheels but they may have been changed by a previous owner from 16in or 17in

The speed discrepancy is quite large though between your speedo and the GPS. Something like 10-12Kmh of a difference in reality (from under-read to over-read) so it may not be down to wheels alone. The car definitely needs to be checked out, regardless.

Best of luck with any appeal you put through.

Kimbot

https://www.boards.ie/discussion/comment/121456609#Comment_121456609

Opel Insignia 2020, standard wheels according to google are 18's

Henry Ford III

So with a 120kph limiter engaged you got a ticket for 129kph average?

There's something wrong there somewhere. I'd imagine the speed cameras are accurate.

Alun

https://www.boards.ie/discussion/comment/121456618#Comment_121456618

18" wheels says nothing ... the tyres you have on them could have a huge variation in aspect ratio and therefore sidewall height, rolling radius and ultimately speedo inaccuracies.

What tyres are on it now, and what are the standard tyres as shown in the manual or the tyre inflation sticker?

Once you know this you can use an online tyre calculator to see the differences including the speedo difference.

https://tire-calc.com/

https://www.boards.ie/discussion/comment/121461271#Comment_121461271

As above.

magicbastarder

https://www.boards.ie/discussion/comment/121456535#Comment_121456535

don't think this would work, and in fact would weaken their case probably - it in no way refutes the evidence that they were speeding; ignorance is no defence; and 'i broke the law because i had a faulty car' will not gain any sympathy whatsoever.

legally your speedo is allowed overstate your speed, within specific parameters. it's not allowed understate your speed, so announcing that your car is illegally reading the wrong speed might not be wise.

Kimbot

https://www.boards.ie/discussion/comment/121461915#Comment_121461915

Well lets just say that the car is all factory, factory wheels tyres etc. Why should the OP be penalised if it can be proven the car was sold with a faulty speedo. TBH how many people actually go and get their speedo calibrated, I would wager not many at all so if I were to buy a car tomorrow, Take it from the showroom and drive through the average cameras on cruise control @ 120kmph but it picks me up @ 135kmph then how am I to know I am speeding when the car itself is telling me I am not?

ohnonotgmail

https://www.boards.ie/discussion/comment/121461937#Comment_121461937

none of that is a defence in court. if the vehicle is fault then his recourse is with the dealer/manufacturer.

Akrasia

https://www.boards.ie/discussion/comment/121462192#Comment_121462192

Yeah. If the courts were to accept 'faulty speedo' as a defence, then every boy racer would be deliberately mis-calibrating their speedo to get off the fine.

Loopholes in the law get exploited very judiciously when it comes to motoring offenses and penalty points

Akrasia

If you're driving at 129kph it would be difficult to not realise that you're actually the fastest car on the road other than those cars that are deliberately speeding.

Regularly having to overtake other cars, many of whom will have cruise control set to 120kph (which is really only about 115kph because most cars are under-reporting their speed should indicate that you're actually going faster than you think you are

If you don't notice this pattern, then the judge can question your situational awareness

Seth Brundle

https://www.boards.ie/discussion/comment/121461937#Comment_121461937

The reality is that you are not going to be able to prove that you were sold a car with a faulty speedo. You could try and argue that your speedo is now faulty but provving that it was faulty whenever you bought it is simply trying to play King Canute with the waves - you can't win that battle simply because you have no evidence that it was faulty when you bought it.

I would offer the OP a small piece of advice - if they were to try and challenge this, they'll lose, no matter what avenue they pursue! If they weren't speeding then they were driving a car that they admit was not roadworthy.

iColdFusion

Check your tyre pressures OP, potentially they are out of whack if the tyres are the right profile but still shouldn't cause a discrepancy of that size.

Calahonda52

The assumption here is that the free sat nav system is correct and that everything else os wrong.

The Russians have been fcuking with it since the start of the war in Ukraine and so have the IDF so......

Finally, as noted ad nauseam here , they are not speed cameras, they are cameras with a time clock so T2-T1 is the issue here.

https://www.boards.ie/discussion/comment/121451901#Comment_121451901

I travel that stretch every couple of months and set my limiter to 120. Never have an issue.

https://www.boards.ie/discussion/comment/121453627#Comment_121453627

I found that 3 points out an extra 50 on my insurance. I then had to be name driver on my wife's car so another 50e . Was an expensive mistake

Oscar_Madison

https://www.boards.ie/discussion/comment/121464311#Comment_121464311

A small price compared to if you had more points - it’s certainly a constant reminder which is actually not a bad thing TBH- it’s the areas where 50kph zone “feels” like a 60kph zone is what can get me - approaching the edge of small towns - but I’ve certainly improved - 80kmph 100kph 120kph always stick to those - just need to keep it easy at the lower speeds

https://www.boards.ie/discussion/comment/121464280#Comment_121464280

As do i, I have not been there in the new car, but usually in my previous ones it was never an issue.

flatty

Just bad luck. Take the points and move on.

Hi,

Just to call and end on this, I think the question was answered. I rang a local solicitor. He said you COULD get a letter and go to court, but the judge on the day may accept it or may so not a chance.

Ultimately its not worth the risk I think of getting 5 points, its a pity thats the way the system is, you have to gamble on it, but im not willing to

Henry Ford III

https://www.boards.ie/discussion/comment/121467285#Comment_121467285

A pragmatic solution. Not ideal though.

p.s. One thought - did you compare your 120kph limiter to a proper GPS reading? (Waze app has a fairly accurate GPS).

magicbastarder

it's not the app which has accurate GPS, it's the device the app is installed on, i would assume?

Waze would just take the info being sent it by the device.

FWIW on my 2012 octavia, my phone (with strava) indicated 80km/h while the speedo said 85.