Laser gun books brick wall for doing 96km/h

MAGPIE · 07-03-2005, 07:47 PM

Quote:

Originally Posted by stuff.co.nz

A BBC TV programme in Britain has demonstrated erroneous readings from laser speed guns, with one device "booking" a brick wall for doing 96kmh and another clocking a stationary car at 8kmh.

The programme was aired to demonstrate the inaccuracy of the devices after a recent case at Inverness Sheriff's Court was dismissed after a laser speed gun recorded 215kmh for a vehicle that was proved not to be capable of exceeding 170kmh.

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Revenue gathering at its worst

: Just imagine a brick wall trying to defend itself in court against this charge

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kiwikid · 07-03-2005, 07:52 PM

yes your honour but i have no motor or wheels to propell me and even more so your honour im concreted to the ground.....

LuvinmyEB · 07-03-2005, 08:01 PM

I wonder where they sent the speeding fine?

Those speeding brick walls can be dangerous...

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FordFan86 · 07-03-2005, 08:07 PM

That poor brick wall :(

MrFlibbles · 07-03-2005, 08:52 PM

i get to work on some police cars here in sa, one of them was kind enough to show me the new speed guns, showed me how it all happens then let me have a go, well i pointed it at a petrol pump and the petrol pump was travelling at 7kmh.... and thay say they are accurate?

Kryton · 07-03-2005, 08:56 PM

i still remember the COMBIE VAN that got booked for doing over 1000kmh through a set of traffic lights.
and you say they arent accurate?

M14A-Mclaren · 07-03-2005, 09:08 PM

Thats so hilarous

lv619 · 07-03-2005, 10:35 PM

I'd say youd have variations in the readings with the operator moving the device etc.
But how are you going to proove them wrong if your booked for a few km's over... no chance in hell.

Paris Hilton · 07-03-2005, 10:37 PM

It probobly works both ways...Could be doing 90 in a 60 area, and it could say 17...

XA-Coupe · 07-03-2005, 10:47 PM

It's really just media beat up. I can set it up that an immobile object gives a reading with no problems at all and the radar/laser woudl still be perfectly ok. It's not tough to do when you think about how they work.

**Full Noise** · 07-03-2005, 11:09 PM

Quote:

Originally Posted by davway

I still remember the COMBIE VAN that got booked for doing over 1000kmh through a set of traffic lights.
and you say they arent accurate?

Davway that has to be bull****. Volkswagen Combie Vans can go much faster than that, their good for at least 1200. :hihi:

: :nutsycuck

: :voldar02:

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TaraHymen · 08-03-2005, 02:12 AM

Quote:

Originally Posted by XA Coupe

It's really just media beat up. I can set it up that an immobile object gives a reading with no problems at all and the radar/laser woudl still be perfectly ok. It's not tough to do when you think about how they work.

i'm interested, how do they work?

LTDHO · 08-03-2005, 08:06 AM

I bet that speeding brick wall is the same one that jumps out in front of you when you're driving!

Spaniard · 08-03-2005, 09:11 AM

Quote:

Originally Posted by LTDHO

I bet that speeding brick wall is the same one that joups out in front of you when you're driving!

I'd say so too!

XA-Coupe · 08-03-2005, 10:02 AM

Quote:

Originally Posted by TaraHymen

i'm interested, how do they work?

Radar is nothign more than radio frequency, the laser is an infra red laser and although they still work on the return of a signal for their readings, FIIK how

point the radar / laser at the wall and the signal will bounce ( returned and the change in frequency is measured ). Set up a moving car / bus whatever behind you and that signal will bounce again off the moving object and hit the wall and reflect back to the radar and give a reading. The bigger the moving object the stronger the signal.

This is why they shouldn't use radars near objects that reflect signals ( like large advertising signs, buildings etc ) as the reading you get may not necessarily be that of the vehicle that you are aiming at. There are procedures for checking the accuracy of the device before the shift and anyone half professional will also make sure that where he sets up doesn't give false readings before they start.

Oh yeah.. and like any mechanical / electrical device.. they can be faulty !

XA-Coupe · 08-03-2005, 10:05 AM

Quote:

Originally Posted by LTDHO

I bet that speeding brick wall is the same one that joups out in front of you when you're driving!

and at 96Kmh they hurt too :1syellow1

XRQTR · 08-03-2005, 10:30 AM

So in effect XA what you are saying is that the boys in blue can actually set up the device to read a few k's more, knowing the speedo percentage rules the average driver wouldnt have a leg to stand on.

Sorry mate but you opened the can.

XA-Coupe · 08-03-2005, 10:38 AM

Quote:

Originally Posted by XRQTR

So in effect XA what you are saying is that the boys in blue can actually set up the device to read a few k's more, knowing the speedo percentage rules the average driver wouldnt have a leg to stand on.

Sorry mate but you opened the can.

buggered if I can see how you arrive at that.

All I am saying is that there are rules and procedures for the use of these things. Should you fail to operate under these guidelines then you render the readings open to error.

For someone to 'set up' something it would rely on a moving object, faster and larger than what you are aiming at being behind them at the exact time required. It would also require a large object to reflect the signal too. I am sure that you can see that the combination of things would be hard to 'set up' just to get a reading a few Ks higher

_2:

**Full Noise** · 08-03-2005, 12:21 PM

Here are few basics of how radars work.
http://electronics.howstuffworks.com...-detector1.htm

Cheers, Danny

TheOtherHalf · 08-03-2005, 01:55 PM

Maybe Pink Floyd was inside the wall singing at 100 decibels....

it: