Does ecilop radar have to have speed locked to issue ticket?

[rastuscat]

I did find the original post, as well as Jantars comments about the High court precedent. Someone may have access to Brookers and may be able to find the original High Court precedent.

Its not correct to say District Court judgements have no legal weight.

They are not considered to be precedent, but they are consider to be influential. That is to say if the district court is unsure of which way to jump, they may use the other district courts decisions as a benchmark.

I'm also very nervous when I hear of police issuing tickets when there are multiple vehicles in the radar beam, and especially nervous when "fastest target" type locking is concerned.

There are a wide range of technical reasons why doppler radar is very unsuitable for use when there are multiple vehicles in the beam.

(1) Doppler radar cannot identify its target
(2) Doppler radar does not know distance to target
(3) Doppler radar "mixes" its transmitted output with the received input (reflection) from the target, and produces ALL the sum, and difference frequencies between its output and its input(s).

Lets look at an imaginary but mathematically correct example.

assumptions for the purpose of demonstration set to use simple arithmetic...

output frequency of radar = 100 demohertz
each km/hr of target vehicle speed towards the radar INCREASES the reflected signal frequency by 1 demohertz

3 vehicles in beam. While they are all at different distances, the size of the reflected signal is essentially the same as they are different sizes and have different radar cross sectional areas.

1 at 103 km/hr - small motorcycle
1 at 105 km/hr - car
1 at 112 km/hr - large truck

Mixer output comprises main signals of

3
5
12 demohertz

as well as minor signals of
5-3 = 2
12-3 = 9
12-5 = 7 demohertz

so the part of the radar unit that determines speed is being fed 2,3,7,9,and 12 demohertz.

The manufacturer uses sophisticated digital techniques to try and determine which signals are valid and should be displayed as strongest signal and fastest signal.

But, ALL the above frequencies (plus and caused by multipath reflections) will all get processed.

The laws of physics mean no one, not even the computer in the radar unit can associate any of those signals 100% accurately with a given target.

Seems you are a tecchie, so thanks for all that. It is all correct, based on my memories of having been a radar tech in the navy 30 years ago. It looks complicated enough to be true, and you got me at the word demohertz.

The emphasis on the radar device is disconcerting, both in the way it is operated and interpreted. In the real world in which it is actually used, the operator should be driving along (or stationary) waiting to see a vehicle moving quickly. He/she should then make a mental estimate of the speed based on his/her experience, and only then use the radar to confirm that. Basically, the visual picture should have at least the same weight in the Popos mind as what the machine displays. I have seen vehicles doing 50 which the radar says are doing more or less, but if the picture I see doesn't tie in with what the radar says, it ain't safe to use the reading. That's the way operators are trained. Tracking history doesn't get the respect it deserves, from either side of the fence.

Thing is, the speed if normally checked a long time before the rider/driver sees the Popo car. That's coz the Popo is actively seeking the traget, but the target doesn't know the Popo is there. Most people don't drive around looking for radar traps (except maybe those on KB). By the time the 'Oh Shit' moment happens, the throttle rolls off and potentially the brakes go on, the speed is locked. Thing is, it's only at that stage that the riders/drivers awareness becomes fairly clear. I've had interesting discussions with people who have suddenly had crystal clear recall of exactly what speed, driving line, traffic interactions they have had in the last 3 months, when told about what was happening around them when their speed was checked.

Still the best advice is to drive at the speed limit, and accept that if you exceed it, the consequences of exceeding it might happen. I don't believe there are as many innocent people given tickets are claim to be.

Totally agree on your mention of the law of physics too. The OP got pinged in Gasson St, where the law of physics tragically caught up with a rider a few weeks ago. The law of physics doesn't grant exemptions or tolerances. Kinetic energy increases with speed. Simple.

[KX500]

Totally agree on your mention of the law of physics too. The OP got pinged in Gasson St, where the law of physics tragically caught up with a rider a few weeks ago. The law of physics doesn't grant exemptions or tolerances. Kinetic energy increases with speed. Simple.

You have great way of putting things - thought provoking.

As well as speed factor in the death in question, Gasson St it self is a danger where three lanes have been squeezed in a st originally designed for two. So tight cannot even allow for parking on the left of the two lanes heading north. And opposite lane parking is so tight you have to make like a vertical pikelet when entering and exiting your car with pies in hand. With a row of cars parked there anyone exiting the stop sign has to pull so far forward onto Gasson to get a clear view and the obvious potential for danger is now there. (Big Kick Ass Blackboards advertising their wares down Marshlands road same thing - especially first vege shop on right heading north past Queen Elizabeth Driver roundabout - hopefully reading this can be proactive on it)

Being seen in my book on a par with the correct speed - like night and day the size of cage drivers pupils when have the bright orange hi vis on - forget the insignificant fluro green most bikers that wear a vis op for. Headlight on high beam always. I've read and experienced people being put down for wearing a hi-glow vis on group rides - I just think are you "Mad or just acting".


The ecilop and his young blond chauffeur were not using a hand-held radar gun - whats the sweep of the in car unit - similar to an infra red beam of an outdoor light ? So doppler radar applies to all radar used by New Zealand police ?

[davereid]

The ecilop and his young blond chauffeur were not using a hand-held radar gun - whats the sweep of the in car unit - similar to an infra red beam of an outdoor light ? So doppler radar applies to all radar used by New Zealand police ?

To the best of my knowledge police use only three types of technologies at the moment, laser (generally hand held or on a tripod) and doppler radar generally car mounted or in the speed camera van. (Fixed Cameras use different technology.)

Laser is not subject to the errors of doppler radar - it has a different set of errors.

Laser can't directly measure speed.

It can only measure distance to target.

So laser works by measuring the distance to target, then a short period of time measuring it again. I have been told this period is 1/100th of a second, but I don't have a manual so cant confirm that.

This creates the problem that if the first measurement was made to the back of the headlight reflector, and the second one came off the front of the headlight reflector, this would create the illusion that the vehicle had moved forward, even if it were stationary, by the depth of the headlight reflector, say 100mm.

Say you are travelling at 100 km/hr or 27.77m/s. In 1/100 of a second you travel 270mm, so a 100 mm error is a detected range of 17m/s to 37m/s or 61 to 133 km/hr.

We don't know how the manufacturers get around this, but the most likely way is to require a series of measurements that all give the same speed. Say a dozen readings.

The more measurements you require the greater the likelyhood that you will have the correct answer. But the harder it will be to get a "lock".

I have experimented with some techniques to help slow the "lock" speed down on lasers. I cant say they work or not, but they seem to as I have always had plenty of time to see a laser unit before lock is obtained.

Heres the counter measures.

(1) Paint numberplate with flat white paint. You can test this with a cheap laser pointer from warehouse stationary. It makes a massive reduction to the reflectiveness of the plate, but is virtually unnoticeable to the eye.

(2) On my car I have a CD stuffed in the front window. Its on the same angle as the windscreen, a steep slope.
It means that if the first reflection comes off the top of the CD, the second off the bottom, the third somewhere else, no lock will be obtained.

(3) I have 3 orange "cat eye" reflectors under my number plate. I have them at 3, 5, and 7 cms behind the number plate, and at different heights so they can all be seen from front of the car. They are much better reflectors than my number plate, so laser pointed at my plate is almost certain to get a refection from one of the reflectors. But its unlikely that a laser operator can hold still enough to get a series of refelctions off any one reflector - and it only takes a reflection off one of the others to stop lock.

(4) I don't actually speed much, really only when overtaking, as I intend to outlive my grandkids.

[The Lone Rider]

.

(1) Paint numberplate with flat white paint. You can test this with a cheap laser pointer from warehouse stationary. It makes a massive reduction to the reflectiveness of the plate, but is virtually unnoticeable to the eye.

(2) On my car I have a CD stuffed in the front window. Its on the same angle as the windscreen, a steep slope.
It means that if the first reflection comes off the top of the CD, the second off the bottom, the third somewhere else, no lock will be obtained.

(3) I have 3 orange "cat eye" reflectors under my number plate. I have them at 3, 5, and 7 cms behind the number plate, and at different heights so they can all be seen from front of the car. They are much better reflectors than my number plate, so laser pointed at my plate is almost certain to get a refection from one of the reflectors. But its unlikely that a laser operator can hold still enough to get a series of refelctions off any one reflector - and it only takes a reflection off one of the others to stop lock.

Pretty sure Mythbusters test all those and found them to not work!

[KX500]

(3) I have 3 orange "cat eye" reflectors under my number plate. I have them at 3, 5, and 7 cms behind the number plate, and at different heights so they can all be seen from front of the car. They are much better reflectors than my number plate, so laser pointed at my plate is almost certain to get a refection from one of the reflectors. But its unlikely that a laser operator can hold still enough to get a series of refelctions off any one reflector - and it only takes a reflection off one of the others to stop lock.

Percy Shaw would be proud Might go score me some of those cop mirror sunglasses from the 80's for good measure

Cheers for all the technical info on the doppler radar - makes for a good case

[Ronin]

Uh oh, people are waking up to the scam... whatever will the govt do about this?

Take it international?

[willytheekid]

This is why I never leave home with out my HD camera on the bike.

As rastuscat has previously mentioned...you just can't argue with video...its dosn't lie!

[davereid]

Pretty sure Mythbusters test all those and found them to not work!

Nothing will stop the laser eventually getting a lock.

But, I have explained the theory behind these counter measures.

The laser manufacturers are not keen to explain how they deal with "slippage" as this may give away trade secrets, help people like me develop countermeasures, or simply demonstrate to the courts that the laser may not be relied on as much as they would like you to believe.

Its my view that all the measures mentioned will have some effect.

Apply occams razor. If the car provided NO reflection then laser would never get a lock. So a poorly reflective number plate must be better than a highly reflective one.

Same as the CD and reflectors. If the device simply gets a reflection from a straight level surface it will obtain the readings it needs easily. If it can't find that straight level surface, it must work much harder.

[willytheekid]

So laser works by measuring the distance to target, then...blah blah blah blah genius waffle rant IQ exceeding waffle waffle DONE!.

Nothing will stop the laser eventually getting a lock.

But, I have explained the theory behind these counter measures....waffle einstein genius amazing facts blah blah lol genius is me waffle waffle tech specs understandy good!

.

Dave=


Me good Idea for lazerery dodging=


...is me smrt now tooo??


posted because Dave is a bastard!...makin us feel like bloody cave men...STOP SHOWING OFF AND GO BUILD US A FLYING BIKE DAVE!!

[awa355]

Some interesting posts. So, would a GPS that records speed position etc as 'Jantar's Garmin be admissible in court as a defence?

Probably not, but might make a 'suspect' officer think twice about pushing a false accusation as happened in Jantars case.

I have been thinking about purchaseing a GPS, mainly for the more accurate speed readout. Are there units specificly suited to motorbikes?

[Jantar]

..... So, would a GPS that records speed position etc as 'Jantar's Garmin be admissible in court as a defence?

Probably not, but might make a 'suspect' officer think twice about pushing a false accusation as happened in Jantars case. .....

Why wouldn't it be admissable? The tracklog id is date/time stamped all the way through. The data recorded is at least as accurate as the data displayed on the cops radar, and is much more accurate than the inbuilt data logger that some cars have and has already been used by the police to get a conviction. Modern GPS does not suffer from the same inaccuracies that the 1st generation GPS units had.

To disallow a GPS record as evidence would mean disallowing ALL electronic evidence.

[jasonu]

Could you please compare apples with apples, your analogy does not pertain to an instant fine.

It doesn't make much sense either.

[KX500]

It doesn't make much sense either.

One is guilty until they prove their innocence the other is innocent until proven guilty.

[rastuscat]

Some interesting posts. So, would a GPS that records speed position etc as 'Jantar's Garmin be admissible in court as a defence?

Probably not, but might make a 'suspect' officer think twice about pushing a false accusation as happened in Jantars case.

I have been thinking about purchaseing a GPS, mainly for the more accurate speed readout. Are there units specificly suited to motorbikes?

Garmin Zumo.

Tom Tom Rider 2 (although this has been superseded by a new model). I have a rider 2.

The difference between bike ones and car ones is that you can punch the bike ones with a gloved hand, and they are normally water resistant. They also bluetooth to a helmet headset, if you have one, and bluetooth to a phone.

There is a mounting on TardMe which makes your car one waterproof, looks like a good deal, coz you can buy car GPS far cheaper than bike ones.

[rastuscat]

To the best of my knowledge police use only three types of technologies at the moment, laser (generally hand held or on a tripod) and doppler radar generally car mounted or in the speed camera van. (Fixed Cameras use different technology.)

Laser is not subject to the errors of doppler radar - it has a different set of errors.

Laser can't directly measure speed.

It can only measure distance to target.

So laser works by measuring the distance to target, then a short period of time measuring it again. I have been told this period is 1/100th of a second, but I don't have a manual so cant confirm that.

This creates the problem that if the first measurement was made to the back of the headlight reflector, and the second one came off the front of the headlight reflector, this would create the illusion that the vehicle had moved forward, even if it were stationary, by the depth of the headlight reflector, say 100mm.

Say you are travelling at 100 km/hr or 27.77m/s. In 1/100 of a second you travel 270mm, so a 100 mm error is a detected range of 17m/s to 37m/s or 61 to 133 km/hr.

We don't know how the manufacturers get around this, but the most likely way is to require a series of measurements that all give the same speed. Say a dozen readings.

The more measurements you require the greater the likelyhood that you will have the correct answer. But the harder it will be to get a "lock".

I have experimented with some techniques to help slow the "lock" speed down on lasers. I cant say they work or not, but they seem to as I have always had plenty of time to see a laser unit before lock is obtained.

Heres the counter measures.

(1) Paint numberplate with flat white paint. You can test this with a cheap laser pointer from warehouse stationary. It makes a massive reduction to the reflectiveness of the plate, but is virtually unnoticeable to the eye.

(2) On my car I have a CD stuffed in the front window. Its on the same angle as the windscreen, a steep slope.
It means that if the first reflection comes off the top of the CD, the second off the bottom, the third somewhere else, no lock will be obtained.

(3) I have 3 orange "cat eye" reflectors under my number plate. I have them at 3, 5, and 7 cms behind the number plate, and at different heights so they can all be seen from front of the car. They are much better reflectors than my number plate, so laser pointed at my plate is almost certain to get a refection from one of the reflectors. But its unlikely that a laser operator can hold still enough to get a series of refelctions off any one reflector - and it only takes a reflection off one of the others to stop lock.

(4) I don't actually speed much, really only when overtaking, as I intend to outlive my grandkids.

The legislation requires that a plate is retroreflective white, not flat white. Keep flat white for your coffees.

Just out of interest, car mounted speed cameras work on a different principle, being slant radar. Still doppler based, but not subject to cosine angle effect.

Odd that someone who doesn't speed much, intending to outlive his grandkids, would put so much effort into making his plate less reflective. I've put no effort at all into doing that, and still haven't had tickets. Simple really, no spid, no spidding tickets.