Thread: What device/s can u use in/on your car to record your vehicle speed accurately?

Hema Explorer app for economic, domestic use or there are many commercial track and record programmes for heavy vehicles.

Police wont accept any vehicle mounted devices such as a gps as proof of speed, about the only thing that would stand up in court would be a speedometer calibration done by an accepted company if such exists.
But even then if a camera or radar says you are speeding you havent got much hope.

Originally Posted by V8Ian

Hema Explorer app for economic, domestic use or there are many commercial track and record programmes for heavy vehicles.

Your domestic use GPS won't cut it. The commerical systems that Trucking Companies use "may" stand up depending on whether u can prove it's accuracy; a yearly calibration history/certificate and then a "Expert Witness" that can validate that the system u are using is accurate, etc.....

Originally Posted by loanrangie

Police wont accept any vehicle mounted devices such as a gps as proof of speed, about the only thing that would stand up in court would be a speedometer calibration done by an accepted company if such exists.
But even then if a camera or radar says you are speeding you havent got much hope.

Not sure about the camera's that takes photo's but there is reports of people winning their cases, but it comes at a HIGH $$ cost as they need to call in expert witness, etc and the system they use has to have some sort of recognition.....

Rob,

A certificate of accuracy for a speedo can be obtained by testing the car on a dynamometer, however that is done with the tyres at a set pressure and condition. The certificate covers accuracy 0-180kph (typically) with up to 3kph diversion (+/-). That's all fine but it won't go toward proving that at the time of any alleged 'overspeed' that your tyres were in good order and at the correct pressure.

Then there's the recording; as stated, any audio/visual record would have its integrity tested in Court, and to defend that you would need an encryption/watermark on the file and a process to manage its security. Then how does the camera clearly show the speedo that is in that car without breaching ADR's for head impact/padded areas of the dashboard/steering wheel...

An option may be to have a (separate) digital speedo fitted that is in camera view, but the purchase, testing, certification and security of the system would be a nightmare for a private individual - which is probably why Government agencies can afford to do it.

At the end of the day, to successfully defend an alleged breach of Road Rule 20 (exceed speed limit), you have to satisfy the Court, not the Police/State Debt Recovery Office or State equivalent, that you didn't do it.

A privately managed observation/recording system would have too many holes in it for a Court to be satisfied if its integrity. I appreciate the result of a 'win' for a transport/truck company but that's only a result in a Local Court - basically an opinion of a Magistrate that can be quoted, but by no means a guide for any other Judicial officer. For it to reach precedence, a decision in a District or higher Court is listed under 'stated cases' and referred to as Case Law and they carry weight for later decisions and even legislative change.

The GPS (system) is operated by the US Government and so its accuracy cannot be certified. It was developed as a military tool and a timing error can be introduced to provide erroneous 'time of flight' for the signal therefore giving incorrect location/speed readings - a good thing to thwart the baddies.

Good idea to provide proof of what you were doing but easiest way (and very simplistic to say) is to not speed (or not speed and get caught ). Remember there is legislation in place to ensure Police/private contracted speed measuring devices are accurate, in addition to the evidence provided via observations of the operator over a period of time and distance that you may not be aware of, which is reasonable considering, and thankfully, that we don't drive around with our eyes glues to a speedo...

Originally Posted by Robmacca

Not sure about the camera's that takes photo's but there is reports of people winning their cases, but it comes at a HIGH $$ cost as they need to call in expert witness, etc and the system they use has to have some sort of recognition.....

Yes , if you can prove that the camera was not calibrated correctly you have a chance but otherwise not worth the cost.

Cheers for that Matt.....

Last year I got pinned for doing 76 in a 60 zone. At the time I didn't believe I was going that fast and when I got home I downloaded the GPS and discovered that I was speeding, but only 68 in a 60 zone. The difference between 76 and 68 is 3pts vs 1pt and obviously more $$. All I was hoping for was to be able to drop the fine down to the 68 level, but this was not to be.....

Originally Posted by mudmouse

Rob,

A certificate of accuracy for a speedo can be obtained by testing the car on a dynamometer, however that is done with the tyres at a set pressure and condition. The certificate covers accuracy 0-180kph (typically) with up to 3kph diversion (+/-). That's all fine but it won't go toward proving that at the time of any alleged 'overspeed' that your tyres were in good order and at the correct pressure.

Then there's the recording; as stated, any audio/visual record would have its integrity tested in Court, and to defend that you would need an encryption/watermark on the file and a process to manage its security. Then how does the camera clearly show the speedo that is in that car without breaching ADR's for head impact/padded areas of the dashboard/steering wheel...

An option may be to have a (separate) digital speedo fitted that is in camera view, but the purchase, testing, certification and security of the system would be a nightmare for a private individual - which is probably why Government agencies can afford to do it.

At the end of the day, to successfully defend an alleged breach of Road Rule 20 (exceed speed limit), you have to satisfy the Court, not the Police/State Debt Recovery Office or State equivalent, that you didn't do it.

A privately managed observation/recording system would have too many holes in it for a Court to be satisfied if its integrity.

The GPS (system) is operated by the US Government and so its accuracy cannot be certified. It was developed as a military tool and a timing error can be introduced to provide erroneous 'time of flight' for the signal therefore giving incorrect location/speed readings - a good thing to thwart the baddies.

Good idea to provide proof of what you were doing but easiest way (and very simplistic to say) is to not speed (or not speed and get caught ). Remember there is legislation in place to ensure Police/private contracted speed measuring devices are accurate, in addition to the evidence provided via observations of the operator over a period of time and distance that you may not be aware of, which is reasonable considering, and thankfully, that we don't drive around with our eyes glues to a speedo...

Matt

Originally Posted by Robmacca

Cheers for that Matt.....

Last year I got pinned for doing 76 in a 60 zone. At the time I didn't believe I was going that fast and when I got home I downloaded the GPS and discovered that I was speeding, but only 68 in a 60 zone. The difference between 76 and 68 is 3pts vs 1pt and obviously more $$. All I was hoping for was to be able to drop the fine down to the 68 level, but this was not to be.....

Probably would have cost a fortune, and the only winners would be solicitors etc. I know people who have elected to have it heard in court just to delay it enough to have points back from previous fines, then go to court and plead guilty. Costs more but they can keep working in the meantime.

Taxis used to have to have their speedos calibrated, as they charge per km and there was an instrument repair business near me who did them. They have gone and I don't know what happens in this age of electronic speedos. Maybe the meter is independent of the vehicle speedo now.

Jeff