Gatso pictures show that car WASN'T speeding

Reezer

Reezer

Reezer

Associate
Joined
27 Oct 2002
Posts
897
My mother received a speeding ticket a few weeks ago but was sure she wasn't speeding so we sent off for the pictures.

I was actually quite suprised when the local speed camera partnership sent the pictures back very punctually. The pictures are amazingly poor - very dark, only show the number plate and white lines, you can't tell where the wheels are or anything. Given that you can only see the number plate, I've had to use that to try and work out how many marks the car has passed and my best guess is 4, rounding up.

Assuming the marks are 5ft apart as they should be some basic maths gives the speed as 27.27 mph. The ticket says 35.

Now, a few questions:

1. How can I be sure my method is correct and that they don't do some "special" angle adjustment to give a higher value?
2. How do we go about contesting it? Do you HAVE to go to court? It seems like a lot of fuss just to get them to double check their pictures. Does anyone know if it is possible to get the camera people to check the photos while you are on the phone and then cancel the ticket if they agree they are wrong? (Assuming I can even find a telephone number!)

Any advice much appreciated.
 
Got to side with Fox on this one! The camera is a precise piece of calibrated equipment. I don't think your mathematical skills are going to get your Mum out of this one!
 
Where the hell did 5ft come from? :confused:

I say send a letter off explaining your calculations to them, I'm sure only good can come of this
 
From what I've just been reading, the majority are 5ft apart but that's not a universal standard.

Also 1 line is the difference between 27mph and 35mph IF they're 5ft apart and IF the pictures are 0.5s apart. It's all a bit too guessy really. Pay the fine and forget it.
 
You'll have to go measure the markings yourself to get an accurate figure. The average is 5 feet apart though.

Calculation you should be using is.

Speed = Gap * Marks * 0.6818 / Interval

ie

4 marks * 5 feet * 0.6818 / 0.5 = 27.272 MPH

To get ~35mph she would have passed 5 marks.
 
In trying to post the images on here I've discovered my mistake - She did cross 5 marks not 4, the 12th gap is less than 1mm on the printed images. It is easier to see on the computer screen than the bit of paper infront of you - it's a strange shiny material.

Anyway, thanks for the advice and in case anyone wanted to see the images out of interest:

dsc02077mu.jpg

dsc02078ma.jpg
 
Dude; parallax error.

You need to extend all the lines on the road to the left, without changing their direction, then see where they meet a piece of the car close to the road, like that rear wheel.

Without the parallax error, the speed will be slower still. It was my understanding of GATSO, that the speed sensor is just to decide if to take the photos, and the photos are the calibrated proof.
 
Last edited:
Your method of calculation on the images is wrong. You're lining up the numberplate at the back with a road line that's beyond the front of the car.

To me it looks like her rear wheel is half way between 4 and 5 in the first pic and past 9 on the second.

That's pretty much 5 lines = 35mph.
 
Last edited:
If she is 100% she was not speeding i say give it a go, realistically she may end up with a bigger fine if she/you are wrong but they need to be caliberated fairly regularly and who's to say it is.

It doe's look like she crossed 5 lines, but everyone deserves their day in court. :)
 
You must log in or register to reply here.
Back
Top Bottom