WA Radio Scanner Users' Group

I was followed by Police and pulled over for speeding in Bullsbrook last night. Without going into specifics (I will not make comment about the offence at the moment as it may be prejudicial to replies to the question), what is the margin for error in relation to the speed reading device used in this circumstance.

I'd say zero.... speed and you'll get caught.

WPXZBP wrote:I'd say zero.... speed and you'll get caught.

I think you're getting the 2 terms tolerance and margin for error mixed up. I am asking about the margin for error.

As far as I'm aware, the in-car units (as you say you were followed by the police) are calibrated on a regular basis. So I would assume that the margin for error would only be slight, and that whatever tolerance they apply would take into account such a margin.

Long story short - if they claim you were speeding, there's every chance that you were. And even if you weren't, it's probably going to be too costly to fight. The path of least resistance is to pay the fine and get on with your life.

As Zebedee has said the officers regularly calibrate their speedo's, Radars, Lazers and camera's thus it's fair to say if you've been pulled over and booked for 10K's over the speed limit then you were doing 10 K's or very close to over the speed limit.

not to mention that when setting up a Speed Camera, they test it with a radar gun to check that the camera is functioning propperly

Just pay the fine

As the rest have said, if you go to a magistrates court and watch someone defend themselves for speeding
they are found guilty about 90% of the time. Bit like no one is guilty in prison right?.

I know it sucks, and it really will cost you less money + headache to just pay the fine and move on.
If you defend yourself, regardless if u win you will still be out of money probably 5x the original ticket price. Sucks but this is our system of justice and making the defendant pay some of the costs helps prevent frivolous lawsuits like in the US.

Besides are you always constantly watching the speedo + speed limits, like checking your speed every 5 seconds.

The manufacturers technical data sheet will specify the device's accuracy (usually -/+ 1 to 2km/h).

herbie1204 wrote: seeing as the car manufacturers are legally allowed to have their speedos out by 10%, i would assume that kind of margin when taking speeds

haha nice answer mate

seeing as the car manufacturers are legally allowed to have their speedos out by 10%, i would assume that kind of margin when taking speeds

yes the device may be more accurate, although they are only calibrated every 12months (or so im told) and the constant setting up, packing up, driving around jolting the equipment will put the instrument out, so the closer to retest date the least accurate, always ask to see the calibration certificate, to see how recently its been calibrated, they are delicate machines, slight bumps will decrease accuracy and you should be certain that its within accepted error margins

(im studying surveying at uni, so i have a background with EDMs and thier operations which is why i raised the point re:callibration certificate)

I don't think the operator would appreciate you approaching them after you've been flashed, I think it wouldn't take long before you had the police around to remove you.

I've got a GPS speedometer in my car and I've driven past multanovas at speedlimit + 5Kms and they haven't gone off. So I'd say the margin is at least speed limit + 5Kms

The accuracy though is a different matter. Can't say I've ever been 'caught' speeding when I wasn't, though...

bakerboy wrote: seeing as the car manufacturers are legally allowed to have their speedos out by 10%, i would assume that kind of margin when taking speeds

Not anymore. Although tolerances are much stricter on post-2006 cars, there's nothing that says that radar guns and cameras have to be calibrated within the same tolerances as car speedometers. (Radars are far more accurate, which sucks if your car's speedo reads low)

Tyranus wrote:I don't think the operator would appreciate you approaching them after you've been flashed, I think it wouldn't take long before you had the police around to remove you.

Especially given recent events

ADR's state the speedometer is not allowed to read less than than the actual speed. Most car speedo's read 6% fast (as allowed by ADR's) but you will usually find the odometer says the correct distance. It is always safer to travel at the indicated speed. If in doubt use your navman or similar to check actual speed vs indicated speed.