what distance do the mobile camera vans get you from?
Discussion
went past one today a bit over the limit however due to traffic slowing from before all cars were quite bunched up so would this mean they only got the first car?, also as the title sugests what distance do the cameras get you from as i was easily within the limit at about 40-50 feet away from it and there were no lines in the road if there was a radar operator in the van then surely they wouldnt be able to get a reading if all the cars were bunched up together?
Don't know how true it is but I remember reading some news in Auto Express a few months back about how the BiB were working on a new camera that could catch you up to a mile a way... No fair! 
Not sure if it was just meant as scare tactics though since there are very few roads where they'd have a clear line of sight up to that distance and they'd have to have some sort of "Sniper" scope fitted.
Not sure if it was just meant as scare tactics though since there are very few roads where they'd have a clear line of sight up to that distance and they'd have to have some sort of "Sniper" scope fitted.
IINM, the operator needs to be able to take a reading off a part of the car that is nearly flat and perpendicular to the length of the radar or laser beam. I believe that, on most cars, from the front they aim for the reg plate.
Were the other cars obstructing the operator's view of your reg plate?
Were the other cars obstructing the operator's view of your reg plate?
wraith said:
Don't know how true it is but I remember reading some news in Auto Express a few months back about how the BiB were working on a new camera that could catch you up to a mile a way... No fair!
Not sure if it was just meant as scare tactics though since there are very few roads where they'd have a clear line of sight up to that distance and they'd have to have some sort of "Sniper" scope fitted.
Not sure if it was just meant as scare tactics though since there are very few roads where they'd have a clear line of sight up to that distance and they'd have to have some sort of "Sniper" scope fitted.
I remember a similar article in the tabloids a few years ago when lidar was first introduced - theoretically this can target over a large distance, but is generally used over a few hundred metres distance.
Edited by alphadog on Wednesday 26th July 07:18
flemke said:
IINM, the operator needs to be able to take a reading off a part of the car that is nearly flat and perpendicular to the length of the radar or laser beam. I believe that, on most cars, from the front they aim for the reg plate.
Were the other cars obstructing the operator's view of your reg plate?
Were the other cars obstructing the operator's view of your reg plate?
Thats what the ACPO Code says they need to do, but in practice all they need to do is point the gun in the general direction of your car, pull the trigger, obtain a reading and then if for whatever reason it is over the prescribed limit, they will 'remember' that they really did watch you going over the speed limit and pull you over.
I have been convicted at 400 metres and other cases are going through at up to 800 metres. If you can hit a number plate from 400 metres, not only are you a better man than I, as I showed in court you would be up to at least bronze medal standard in shooting at the last olympics.
Of course, this would also assume that as in the olympics the target, in this case the number plate is stationary........!
Once you take into account that the number plate may be moving at 70 mph you can see how farsical the accuracy that is claimed is!
justinp1 said:
flemke said:
IINM, the operator needs to be able to take a reading off a part of the car that is nearly flat and perpendicular to the length of the radar or laser beam. I believe that, on most cars, from the front they aim for the reg plate.
Were the other cars obstructing the operator's view of your reg plate?
Were the other cars obstructing the operator's view of your reg plate?
Thats what the ACPO Code says they need to do, but in practice all they need to do is point the gun in the general direction of your car, pull the trigger, obtain a reading and then if for whatever reason it is over the prescribed limit, they will 'remember' that they really did watch you going over the speed limit and pull you over.
Indeed. And without the proper aiming, the slip error can push up the recorded speed anyway.
I understand the LTI-2020 is approved for 999m.
At that distance according to the makers data the beam spread is a 3m ellipse. That means that at the edge of the ellipse the power is half peak power so the true light 'blob' is a bit bigger.
I have seen other data which shows there are 2 ellipses either ide of the main 'blob'
However at that spread light is reflected off many other things travelling at different sppeds such as the car overtaking you or the car passing in the opposite direction.
I'm sure there are a few who actually think that the laser light will be a tiny red dot a few mm across accurately landing on the numberplate. The aiming cross hairs in the video help to foster this misconception
At that distance according to the makers data the beam spread is a 3m ellipse. That means that at the edge of the ellipse the power is half peak power so the true light 'blob' is a bit bigger.
I have seen other data which shows there are 2 ellipses either ide of the main 'blob'
However at that spread light is reflected off many other things travelling at different sppeds such as the car overtaking you or the car passing in the opposite direction.
I'm sure there are a few who actually think that the laser light will be a tiny red dot a few mm across accurately landing on the numberplate. The aiming cross hairs in the video help to foster this misconception
You can actually easilly test to see what the dispersion pattern is even though you can't see it.
You use a reflective object (ideally preferentially reflective such as a number plate or road sign) with a 'dull' background (such as a field, or the sky even) and fire the Pro Laser at it with the trigger held. You'll get a range reading. The move the head up display spot left to right/up down etc. The range reading will turn to hiphens with no reflected signal, and back to a range reading when there is. You can then more or less work out the dispersion pattern.
The crosshairs do indeed create an illusion of bright 1 photon wide red spot though!
not anything like the case.
Number plates are bloody reflective though, and slip errors are pretty hard at range, but you CAN slip along street furniture. especially crash barriers, and for some reason black house guttering!
You use a reflective object (ideally preferentially reflective such as a number plate or road sign) with a 'dull' background (such as a field, or the sky even) and fire the Pro Laser at it with the trigger held. You'll get a range reading. The move the head up display spot left to right/up down etc. The range reading will turn to hiphens with no reflected signal, and back to a range reading when there is. You can then more or less work out the dispersion pattern.
The crosshairs do indeed create an illusion of bright 1 photon wide red spot though!
not anything like the case.
Number plates are bloody reflective though, and slip errors are pretty hard at range, but you CAN slip along street furniture. especially crash barriers, and for some reason black house guttering!
Richard C said:
At that distance according to the makers data the [LTI-2020] beam spread is a 3m ellipse.
Actually the pattern is in the form of 3 distinct vertical bars, perfect for missing the vrm (even when the device is aligned and aimed correctly) heence sweeping across some other surface - a motorbike can even fit in-between them….
wraith said:
Don't know how true it is but I remember reading some news in Auto Express a few months back about how the BiB were working on a new camera that could catch you up to a mile a way... No fair!
Not sure if it was just meant as scare tactics though since there are very few roads where they'd have a clear line of sight up to that distance and they'd have to have some sort of "Sniper" scope fitted.
Not sure if it was just meant as scare tactics though since there are very few roads where they'd have a clear line of sight up to that distance and they'd have to have some sort of "Sniper" scope fitted.
Imagine the aiming skill needed to hit a car with a laser at 1 mile.
Forums | Speed, Plod & the Law | Top of Page | What's New | My Stuff