Mistaken identity?

[Number 5]

That's really interesting, so where do they aim on a motorcycle, or where are they told to aim...? Good luck with the case!

Thats my point, it says it must be pointed at a flat reflective (as to return the beam) surface, between the headlights, as halogen lights affect the laser beam.
Now this is where I got curious, pointed at a motorcycle it would be affected by the headlight, as I always have the headlight on (can't turn it off), so how are they instructed to operate against motorcyles?????, no one seems to know, and there is no policy or instruction in the police manual.

Also how would it affect the reading of the laser from side on around a bend, as the motorcycle would be banked over, therefore the laser beam would first be deflected to ground before returning to the gun to record a reading.

[scumdog]

Thats my point, it says it must be pointed at a flat reflective (as to return the beam) surface, between the headlights, as halogen lights affect the laser beam.
Now this is where I got curious, pointed at a motorcycle it would be affected by the headlight, as I always have the headlight on (can't turn it off), so how are they instructed to operate against motorcyles?????, no one seems to know, and there is no policy or instruction in the police manual.

Also how would it affect the reading of the laser from side on around a bend, as the motorcycle would be banked over, therefore the laser beam would first be deflected to ground before returning to the gun to record a reading.

At 230+ metres away it's plurry hard to tell what part of the bike the beam is hitting..all I know is it works.

[Number 5]

At 230+ metres away it's plurry hard to tell what part of the bike the beam is hitting..all I know is it works.

It works as it gives a reading, but is it an accurate reading, and if its hard to tell what part of the motorcycle its hitting, there is a clear case of doubt.
The daily/pre-deployment testing is against a police car with a certified accurate speedometer (+/- 3kph), but the operation policy does not specify any testing against motorcycles, how can we be assured we are not being penalised when there is no assurance of the accuracy of the equipement.
The annual accuracy testing is done in a lab against an international standard, but again not against motorcycles.

[Matt_TG]

Don't shoot me down here as I'm no expert but my thinking is it wouldn't really matter where it hit on the target vehicle (bike or car) as long as it bounced back to register a return signal.

You could argue that there are less flat areas on a bike to reflect a perpendicular signal so therefore you are less likely to get a reading, any other signals will bounce off in all directions, and if they hit something else on their way back to the gun it would be longer than the most direct distance anyway?

At the end of the day "it works" as Scumdog said.

I still think Steve is extremely unfortunate and hope he can get things sorted.

[scracha]

You're wasting your time writing them a polite letter. Same thing happened to me. They don't give a fuck. Pay the fine and get your money's worth by speeding excessively for the next couple of months.

[Jantar]

Don't shoot me down here as I'm no expert but my thinking is it wouldn't really matter where it hit on the target vehicle (bike or car) as long as it bounced back to register a return signal.

You could argue that there are less flat areas on a bike to reflect a perpendicular signal so therefore you are less likely to get a reading, any other signals will bounce off in all directions, and if they hit something else on their way back to the gun it would be longer than the most direct distance anyway?

....

With radar that is correct. It works on the dopler principle so the actual part of the target that is reflecting isn't important.

Laser, though, works on the difference in time taken from send to receive of succesive bursts of light. In this case the point of impact with the target is important. By sliding the laser beam along a surface the speed recorded is the speed that the beam is moving, not the speed that the target is moving. That is why a specific part of the vehicle (eg number plate) is targeted. It avoids the main cause of a false reading.

The cop who ticketed the OP would have radar in his moving vehicle. Laser can only be used when stationery.

[NighthawkNZ:Me]

Know about police radar
http://www.delonixradar.com.au/new_zealand/

[quickbuck]

Not too much embelishment. I have witnessed him inverted at less than 100' and travelling at over 360 kts. But that is what he was trained to do back in the days we still had an airforce.

Hey, we still have one.....
Just a shame Jim can't fly the current A/C he is on inverted at all.......

It was a buzz to see all the Helo's up the other day.
Made me proud......
Never thought I would be, as I used to a die hard Jet fan... Yes, I did get to fix the Strikemasters and Aermacchis of 14 Sqn, and Skyhawks on 75, and the Gas Turbines (Jet Engines) in between times.

Even went Flying in a Strikemaster with Jim. Went cloud chasing. Was a real buzz.

Anyhow, back to the topic.....
If you can be bothered fight it... But for me personally I would just pay the fine, as there are many times I have had a lapse in selkf disipline and might have not keeped within the law.... and didn't get caught.
So I would just look at it as paying for one of those times.....

Yep, the points rip. BUT when I was young and silly I dot 95 within 6 days on my CBR 400..... I managed to keep my nose clean for two whole years!

[quickbuck]

That's a bit tough. Most speedos read a bit fast and an indicated 108 could well be nearer 100 actual kph. Or if it was over that it likely wouldn't be by much.

I know for a fact mine is spot on at the moment.
I had a nice Policeman stand at the end of a Taxiway pointing the radar gun at me to check it at 100k.....
Shame my front tyre is at the lower limit for tread.....

[Number 5]

With radar that is correct. It works on the dopler principle so the actual part of the target that is reflecting isn't important.

Laser, though, works on the difference in time taken from send to receive of succesive bursts of light. In this case the point of impact with the target is important. By sliding the laser beam along a surface the speed recorded is the speed that the beam is moving, not the speed that the target is moving. That is why a specific part of the vehicle (eg number plate) is targeted. It avoids the main cause of a false reading.

The cop who ticketed the OP would have radar in his moving vehicle. Laser can only be used when stationery.

That is exactly my point in my case against a laser gun (a 1970s Pro Laser 2, not the latest LT20 technology), but also remember what I detailed from the police manual about pointing it at headlights,which from research seems to be one of the key elements of false readings on all vehicles.

One funny comment in manual, infact it was the first paragraph stating that,
"The manufacturersoperational manuals for radar and laser speed detection systems used by the NZ police are inappropriatefor the New Zealand environment. For this reason this module and the New Zealand Operators Manual are the only documents detailing the manner of operation".

What is so different about the NZ environment!!!!!!!!!!!!.

Wonder if this has anything to do with what the manufacturers manual states "to avoid movement of the gun which would give false readings this equipement must be used on a tripod

In regards to the radar in patrol cars, it cannot be specifically directed at a vehicle, so any other vehicle on either side of the road can cause a mis-reading , so as in a photo shot speed camera, benefit of doubt is instructed to be considered.

[MaxB]

This is a website for a BBC TV program that used to be online that discusses some of the issues around LIDAR.

http://www.bbc.co.uk/insideout/south...-cameras.shtml

Some US states are considering phasing out portable laser units altogether but some commentators suggest it has more to do with training and budget issues. Fixed cameras are a lot cheaper especially if they are farmed out to contractors and they can rake in the $$$.

That is exactly my point in my case against a laser gun (a 1970s Pro Laser 2, not the latest LT20 technology), but also remember what I detailed from the police manual about pointing it at headlights,which from research seems to be one of the key elements of false readings on all vehicles.

One funny comment in manual, infact it was the first paragraph stating that,
"The manufacturersoperational manuals for radar and laser speed detection systems used by the NZ police are inappropriatefor the New Zealand environment. For this reason this module and the New Zealand Operators Manual are the only documents detailing the manner of operation".

What is so different about the NZ environment!!!!!!!!!!!!.

Wonder if this has anything to do with what the manufacturers manual states "to avoid movement of the gun which would give false readings this equipement must be used on a tripod

In regards to the radar in patrol cars, it cannot be specifically directed at a vehicle, so any other vehicle on either side of the road can cause a mis-reading , so as in a photo shot speed camera, benefit of doubt is instructed to be considered.

[davereid]

Laser, though, works on the difference in time taken from send to receive of succesive bursts of light. In this case the point of impact with the target is important. By sliding the laser beam along a surface the speed recorded is the speed that the beam is moving, not the speed that the target is moving. That is why a specific part of the vehicle (eg number plate) is targeted. It avoids the main cause of a false reading.

Yep.

Laser is almost certain to produce incorrect readings if targetted at a headlight. The software in the laser discards those it can tell are wrong, thus allowing it to give a (usually) accurate reading.

Heres how the error occurs.

You are travelling at 50km/hr (about 12m/s) towards the LIDAR.

It sends a pulse of light out which hits your number plate and is reflected. The LIDAR know knows the distance away you are.

1/100th of a second later, it does the same thing with the same result, except you are 0.12 metres closer. Therefore you are doing 50km/hr.

Headlight error..
You are travelling at 50km/hr (about 12m/s) towards the LIDAR.

It sends a pulse of light out which hits your headlight, at the back of the reflector and is reflected. The LIDAR know knows the distance away you are.

1/100th of a second later, it does the same thing except the beam is this time relected from the front of the reflector. As before you are 0.12 metres closer. But the LIDAR thinks you are 0.12m plus the 0.06m caused by the slope of the refector onyour headlight.

Therefore you are doing 75km/hr as measured by the LIDAR.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is why some canny drivers put a CD in the window of the car.
It is on an extreme slope, and is a very good LIDAR reflector.

It doesnt stop the LIDAR working.

But as there are lots of errors in the returned signal, the LIDAR software keeps discarding incorrect ones.

This often provides the driver with the time to see the LIDAR operator, and slow down.

[Number 5]

Yep.

Laser is almost certain to produce incorrect readings if targetted at a headlight. The software in the laser discards those it can tell are wrong, thus allowing it to give a (usually) accurate reading.

Heres how the error occurs.

You are travelling at 50km/hr (about 12m/s) towards the LIDAR.

It sends a pulse of light out which hits your number plate and is reflected. The LIDAR know knows the distance away you are.

1/100th of a second later, it does the same thing with the same result, except you are 0.12 metres closer. Therefore you are doing 50km/hr.

Headlight error..
You are travelling at 50km/hr (about 12m/s) towards the LIDAR.

It sends a pulse of light out which hits your headlight, at the back of the reflector and is reflected. The LIDAR know knows the distance away you are.

1/100th of a second later, it does the same thing except the beam is this time relected from the front of the reflector. As before you are 0.12 metres closer. But the LIDAR thinks you are 0.12m plus the 0.06m caused by the slope of the refector onyour headlight.

Therefore you are doing 75km/hr as measured by the LIDAR.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is why some canny drivers put a CD in the window of the car.
It is on an extreme slope, and is a very good LIDAR reflector.

It doesnt stop the LIDAR working.

But as there are lots of errors in the returned signal, the LIDAR software keeps discarding incorrect ones.

This often provides the driver with the time to see the LIDAR operator, and slow down.

Great info, and thanks, but from the information I have gathered it is the infra red spectrum in the halogen light source that also affects the laser reading, other errors are caused by slippage (laser moving along the side of the vehicle, and not at the front (cosine angle), this is also recognised in the NZ police manual), also from the NZ manual - undulating services also give incorrect readings, ie dip in the road, coming down a hill, round a bend.

The stated operating procedure is a straight, level road of more than 250 metres.

Another interesting snippet of information from the NZ police manual is that it states incorrect readings when used in a certain manner would be in favour of the driver!!! ie doing 60 may record on the laser as 40kph.
This is in direct conflict of what the manufacturers state, and also proven on some of the links listed in this forum, especially by the work undertaken by Dr Clarke in the UK.
Could this be another case of the unique NZ operating environment!!!!!!!.

[Number 5]

Yep.

Laser is almost certain to produce incorrect readings if targetted at a headlight. The software in the laser discards those it can tell are wrong, thus allowing it to give a (usually) accurate reading.

Heres how the error occurs.

You are travelling at 50km/hr (about 12m/s) towards the LIDAR.

It sends a pulse of light out which hits your number plate and is reflected. The LIDAR know knows the distance away you are.

1/100th of a second later, it does the same thing with the same result, except you are 0.12 metres closer. Therefore you are doing 50km/hr.

Headlight error..
You are travelling at 50km/hr (about 12m/s) towards the LIDAR.

It sends a pulse of light out which hits your headlight, at the back of the reflector and is reflected. The LIDAR know knows the distance away you are.

1/100th of a second later, it does the same thing except the beam is this time relected from the front of the reflector. As before you are 0.12 metres closer. But the LIDAR thinks you are 0.12m plus the 0.06m caused by the slope of the refector onyour headlight.

Therefore you are doing 75km/hr as measured by the LIDAR.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This is why some canny drivers put a CD in the window of the car.
It is on an extreme slope, and is a very good LIDAR reflector.

It doesnt stop the LIDAR working.

But as there are lots of errors in the returned signal, the LIDAR software keeps discarding incorrect ones.

This often provides the driver with the time to see the LIDAR operator, and slow down.

Forgot to mention in the last post - you are correct in your statement regarding the LIDAR software, but to my knowledge that relates to the latest LT20 laser gun, the equipment I was stopped with was a Pro Laser 2, 1970s technology from Kingston Electronics, which doesn't have this facility.

[Patrick]

It works as it gives a reading, but is it an accurate reading, and if its hard to tell what part of the motorcycle its hitting, there is a clear case of doubt.
The daily/pre-deployment testing is against a police car with a certified accurate speedometer (+/- 3kph), but the operation policy does not specify any testing against motorcycles, how can we be assured we are not being penalised when there is no assurance of the accuracy of the equipement.
The annual accuracy testing is done in a lab against an international standard, but again not against motorcycles.

You're right. Ban all motorbikes, as they are clearly above the law....

...Laser, though, works on the difference in time taken from send to receive of succesive bursts of light.

The speed of light... 180,000km per second (from memory... allbeit booze and alzheimers affected now...... )

Imagine that number showing up on the screen. What would the fine be?

......

What is so different about the NZ environment!!!!!!!!!!!!

NZ has KB. Some think they are exempt.

This is why some canny drivers put a CD in the window of the car.
It is on an extreme slope, and is a very good LIDAR reflector.

It doesnt stop the LIDAR working.

Fluffy dice work better. The brighter the colour, the better.