Speedometer calibration and case laws

What sort of case law is out there with regards to speedometer calibration in police vehicles? Is officers testimony that it was calibrated sufficient, or is some kind of documentation required?

Thanks

In one of many seminars I attended over the years, the gentleman who was presenting said "in God we trust, everyone else must provide evidence"

Sadly, the courts take officer's testimony as "evidence"

In the world of metrology, no matter how dismal or serious, from a minor industrial calibration to pharmaceutical calibrations, there must exist documents that prove your claims.

If I take that same principal and apply it to police cruisers, each vehicle should have a certificate that shows, when, where and how the speedometer was calibrated and who performed the test.

As an auditor, you can dig as deep as you like, the capabilities of the lab/facility that conducted the test, the trading of the tech who did the work, the equipment used and the procedure...

jsherk said it best, out politicians are a joke, but that's not because they don't know what's going on, it's because it works out this approach yields higher return financially.

As far as Lidar, if you assume it's an infallible instrument, you are sadly mistaking, every instrument has it's advantages and disadvantages. If used correctly and properly, the advantages will out weight the disadvantages.

R. v. Bland seems to be the go-to decision with regard to speedometer calibration. JPs seem to think that if the speedometer is capable of showing a steady speed then it must be working correctly. TRUE in a sense, but that doesn't mean it is showing the correct speed. I mean if I tune one of my guitar strings flat it will play the same wrong note all night. By JP logic I should tune it once when I buy it and then only when a string breaks.

R. v. Violi is a more recent one from 2011 wherein the officer testified that the speedometer was calibrated sometime in the year before. No documentation provided. Also I'm not sure if police in the Region of Peel use winter tires but if they do shouldn't that trigger a speedometer calibration? Being a year later they would have switched the tires twice already. Paragraph 9 is particularly interesting. In this one the JP used the reason "defence didn't provide evidence contrary to speedometer accuracy" for conviction. Perhaps the proper defence here would have been to take the stand and say "my speedometer said 100km/h". Since neither has been calibrated = reasonable doubt?

With all of the testing and calibration required for radar and LIDAR and all the cases that get dismissed because of it, and the fact that apparently none of this is required for "pacing", you'd think that more police departments would be using their infallible speedometers instead.

Observer135 wrote:

As far as Lidar, if you assume it's an infallible instrument, you are sadly mistaking, every instrument has it's advantages and disadvantages. If used correctly and properly, the advantages will out weight the disadvantages.

But an OPP officer told me "we got lasers, they're hunderd percent accurate!"

speedo's have a +/- 10% accuracy

and modern speedo's are pretty damn accurate not like back in the day, a lot of it is digital technology, albeit on a analogue display.

What I want to look into is that since the OPP radar (Genesis II) test requires that they test it against a vehicle of known speed (which is usually the patrol car itself that it is mounted in), you have an issue where "the radar speed matched the speedometer speed". But if the speedometer is not calibrated then you have a problem... yes they matched each other, but that does not mean that either of them is reading accurately. They could both be off by the same amount!

"How do you know the radar was accurate? Because it matched the speedometer!"

"How do you know the speedometer was accurate? Because it matched the radar!"

the speedo is going to be accurate +/- 10, if its a digital readout, it's going to be balls on accurate

unless rims/tires are NOT OEM

Radar accuracy is 100%. The speed shown will be within 1 unit of measure, due to the fact that radar can obtain a speed with a whole number and partial number (example: 125.9Km/H) the radar, will only produce the whole number, being 125Km/H in this example. The partial number is truncated down to the whole number. As for the speedometer accuracy: the speedometer and radar do not have to show the same number to be accurate. As a part of the radar testing procedures, the officer must do a road test. So, if the radar is showing the partol speed to be 100Km/H, the speedometer does not have to also say 100Km/H, it's nice if it does, however, it can actually say 99, 98, even 97Km/H, or going high showing 101, 102 or 103Km/H. What is important is the relationship between the two is the same each time. So you cannot be high at 102 for one reading and then the next speed stop the radar was showing 98Km/H, it must be up to 3Km/H high or low, the same, for each reading. The difference in the speedo / radar speed is only due to the speedometer of the cruiser being off. If there is a cruisers speedo that says "Certified" calibration, that is generally there for show....

Well again this a problem...

If there is no proof the speedometer is actually reading correctly, then just because the radar says the same as the speedometer, does not make the radar correct either.

Gas pumps have to be calibrated and certified every now and then to a known standard (the litre) to make sure that when it says 1 litre on the pump you are actually getting 1 litre out of it. It think it is Weights and Measures Canada that does this test.

The problem with radar and speedometers is that they are not testing to a known standard. The tuning forks solved this problem with radar because they could be calibrated and certified accurate to a specific "speed" which you would then know the radar was also accurate. Not sure how you calibrate a speedometer, but I am sure there are ways to test it against a known.

Radar is only accurate to +/- 1 km/h IF they are calibrated against a known standard.

I am sure speedometers also have +/- factore for their accuracy as well, but they too need to calibrated against a known standard.

Anyways, the point of this thread was to see if there was any specific case laws where the courts have stated that speedometers either do or do not need to be calibrated.

If tuning forks were required by law, they would be used, they are not. If the manufacturer said they definitely need to be used, they would be. Decatur cried the day tuning forks were no longer being used because they sold a lot of them to the various pd's as they would get lost a lot and have to be re ordered...Decatur never came out and said they were required just to keep sales up. Decatur knows they were not necessary so they stopped selling them with the radar units. As well, the radar manual does not say the radar must ber checked against a vehicle of a known speed, it does say the speedo on the car and the patrol speed indicated on the radar must be in agreement...Anyways, the point of this thread was not about tuning forks or radar accuracy, I apologize.