Court dumps the speeding ticket

[davereid]

My buddy was given a speeding ticket, 117 in 100 zone from a mobile cop using Stalker DSR. He didn't think he was speeding so decided to take it to court.

Court agreed. Found the cop was trained on radar in 1999 - that was the date of proficiency certificate. So it only applied to Stationary Radar, as stalker DSR mobile radar was not around.

Also, the certificate of calibration of the radar was dodgy, but was not admittied as evidence. Certificate was based on assumption that tuning forks are infallible - Police could not show they had been checked to a standard.

So if you think you got a ticket unfairly check the cop has a certificate of proficiency on MOBILE radar if applicable and ask the police to show how they know the tuning forks are OK.

Cheers Dave

[Da Bird]

My buddy was given a speeding ticket, 117 in 100 zone from a mobile cop using Stalker DSR. He didn't think he was speeding so decided to take it to court.

Court agreed. Found the cop was trained on radar in 1999 - that was the date of proficiency certificate. So it only applied to Stationary Radar, as stalker DSR mobile radar was not around.

Also, the certificate of calibration of the radar was dodgy, but was not admittied as evidence. Certificate was based on assumption that tuning forks are infallible - Police could not show they had been checked to a standard.

So if you think you got a ticket unfairly check the cop has a certificate of proficiency on MOBILE radar if applicable and ask the police to show how they know the tuning forks are OK.

Cheers Dave

What you are saying is a bit ambiguous. Are you saying that the cop didn't have a Certificate of Proficiency for mobile radar or are you saying that he did have a certificate for mobile radar but the court threw the case out because he was trained in 1999 when Stalkers were not even in NZ?
The actual principles of how radar operates etc hasn't changed, just the units (and some functions) so can't see how a judge could throw a case out based on someone being trained in 1999.

BC.

[What?]

...so can't see how a judge could throw a case out based on ...

Shouldn't be hard to figure out if you look at some of the judgements made and sentences given in criminal cases...

[Lou Girardin]

The actual principles of how radar operates etc hasn't changed, just the units (and some functions) so can't see how a judge could throw a case out based on someone being trained in 1999.

BC.

Most cops can't spell Doppler, let alone explain it. But what you're saying is that, if a cop trained to use the old Smith and Wesson .38's, he's quite capable of safely using a Glock.

[Da Bird]

Most cops can't spell Doppler, let alone explain it. But what you're saying is that, if a cop trained to use the old Smith and Wesson .38's, he's quite capable of safely using a Glock.

Yip, I've used both and haven't killed anyone by mistake yet. (I've read the instruction manual).

[davereid]

I can't remember the exact wording, but the police training certificate said something like "Fred bloggs has been trained on, and is proficient in the operation of stationary radar speed enforcement equipment"

But, although not admitted in court - and it wasn't needed, the police had done a simple 2 point calibration on the radar using tuning forks. They didn't appear to be able to establish the standard used to calibrate the tuning forks.

Maybe some of the police on site can comment on if the tuning forks are traceable to a national standard.

I must say, that I was not impressed by the calibration document. I'm a registered engineering associate, and I felt the calibration was shoddy, as no data except the two test points ( and admission of a 0.6km/hr offset error) was provided.

[spudchucka]

Maybe some of the police on site can comment on if the tuning forks are traceable to a national standard.

The tuning forks each have their own serial number. Once a year the whole unit gets taken out of the car and sent away for checking / recalibration. The tuning forks are used as part of your daily checks done to ensure that the unit is functioning correctly.

[Pixie]

Yip, I've used both and haven't killed anyone by mistake yet. (I've read the instruction manual).

Yeah,but a few of your compatriots have put Glock bullets in their lower extremities

[Jantar]

So a tuning fork, that isn't moving but just vibrating, can give a reading of 50 kmh. A second tuning fork, that isn't moving but just vibrating, can give a reading of 100 kmh. Put them both together and get a reading of 150 kmh.

But how about if the tuning fork is also moving at say 10 kmh, what speed will the radar unit give? And if a vehicle aproaching the radar at 50 kmh has something vibrating at a steady standing wave frequency, will it cause any error in the radar's reading?

[craigs288]

Spudchucka. I would like you to clarify your statement.

Are you saying that the radar is removed and calibrated once a year, in an accurate and detailed manner by an appropriately authorised technician or engineer?
And that the tuning forks are used by the officer prior to use on a daily basis to verify the unit is within the specified allowable error (+/- 0.6km/h)?
To repeat someone else's question, how often are the tuning forks checked for accuracy, and to which/what international standard, if any?
Is there an assumption that the tuning fork will never change, even if dropped or bent, or even due to temperature changes? Which will obviously affect the fundamental frequency of the tuning fork.

Just wondering.
Also wondering if I have the right to demand that the certificate of proficiency of the officer, the calibration certificate of the radar, and also some sort of certification of the tuning forks are all current and correct before I even begin to accept that my speed was recorded accurately?

Do I also have the right to demand that the radar and tuning forks are retested after the date on which I was cooked with radar, to ensure they had not become unacceptably unaccurate between their last calibration and the date I was issued with a ticket?

I would like to think I have the rights to ask these questions and demand accurate answers, considering that my taxes pay for this equipment and the police wages. I would also like to think that I have the right to demand that they prove the "crime" I committed beyond a reasonable doubt, rather than just assuming they are correct and accept the outcome.

[craigs288]

In response to Jantar's comments.

I would have thought that if you had two tuning forks whos frequencies relate to 50 and 100km/h, vibrating at the same time, the radar would display which ever produced the strongest output (amplitude/volume), or if they were perfectly equal should produce the average of the two frequencies and come up with 75km/h.

[scumdog]

Spudchucka. I would like you to clarify your statement.

Are you saying that the radar is removed and calibrated once a year, in an accurate and detailed manner by an appropriately authorised technician or engineer?
And that the tuning forks are used by the officer prior to use on a daily basis to verify the unit is within the specified allowable error (+/- 0.6km/h)?
To repeat someone else's question, how often are the tuning forks checked for accuracy, and to which/what international standard, if any?
Is there an assumption that the tuning fork will never change, even if dropped or bent, or even due to temperature changes? Which will obviously affect the fundamental frequency of the tuning fork.

Just wondering.
Also wondering if I have the right to demand that the certificate of proficiency of the officer, the calibration certificate of the radar, and also some sort of certification of the tuning forks are all current and correct before I even begin to accept that my speed was recorded accurately?

Do I also have the right to demand that the radar and tuning forks are retested after the date on which I was cooked with radar, to ensure they had not become unacceptably unaccurate between their last calibration and the date I was issued with a ticket?

I would like to think I have the rights to ask these questions and demand accurate answers, considering that my taxes pay for this equipment and the police wages. I would also like to think that I have the right to demand that they prove the "crime" I committed beyond a reasonable doubt, rather than just assuming they are correct and accept the outcome.

Question (1): YES!

The part about 'do I have the right to demand....etc', yes, but not at the side of the road (most of the documentation is not carried in the car in the first place) but you will get it in disclosure if requested when you plead not guilty.

[craigs288]

I plan to wait until the first reminder turns up and then write a polite letter asking for all of that information.
If they provide it and it's all accurate then I have to accept that I am paying a fine for my indiscretion.
But until that day my position is 'innocent until "proven" guilty'. Not 'guilty because he said so'.

[boomer]

Yip, I've used both and haven't killed anyone by mistake yet. (I've read the instruction manual).

firing blanks BC??

[davereid]

Hi..

Doppler radar 101....

The radar transmitter sends out a steady signal. The actual frequency varies between units but actually, its not particularly important, as it doesnt effect the measured speed.

If the transmitted signal hits a stationary object, it is reflected, and arrives back at the radar gun at exactly the frequency it was transmitted.

If the target is travelling towards the radar unit the reflected signal will arrive at a higher frequency. If the target is travelling away from the radar unit the reflected signal will arrive back at a lower frequency.

Its as easy as taking the speed of light.. and adding the 27m/s you are travelling at 100km/hr. Don't bother doing the math... it results in about a 19hz change in the reflected signal for every 1km/hr the target vehicle is doing.

So, how does the tuning fork work ?

Well it vibrates at an (allegedly) known frequency. And when it accelerating (vibrating) towards the radar it gives the "approach" signal. When its vibrating away from the radar it gives the "depart" signal.

So during a calibration with a tuning fork, the radar unit thinks it is looking at a vehicle. The calibration technique is fine, as long as the tuning fork vibrates at its rated frequency.

Radar units which can determine the direction of travel of a target vehicle won't be able to determine the direction a tuning fork works in ! It will respond to both approaching and departing vehicles.

Practical considerations...

Due to the way doppler radar works, some things are very important.

Doppler radar cannot identify its target. It does not know if its looking at the motorcycle or the truck. It does not allow an estimation of distance (although this is not impossible) - the police officer makes that decision based on experience. (ie he makes a guess !)

Doppler radar can track a number of targets, as it can recieve signals of different frequencies all at once. But it cant associate any reading with any target. Once again, if there are multiple vehicles in the beam, the operator will assess which is the target.

This is significant for bikers. Your vehicle may be the closest... but its a very poor radar target. Large flat surfaces like trucks will be a bigger radar target, even when they are optically a dot in the distance.

ie optical size and radar size are unrelated.

Secondly, a two point calibration on a radar unit does not show it is accurate except at the two speeds tested. Other sppeds are calculated using a linear equation ie y=mx+c. The multiplier is critical, and a small error at 40km/hr is huge at 160.

Have a look at my web page http://www.eslnz.com/radar.html for more data.

My apologies if the info on the button/display layout on the stalker is wrong.. my local police won't let me dismantle it to check...