Caught by the sound of your speeding engine!

William

William

William

Soldato
Joined
26 Jul 2003
Posts
10,948
Location
Derby
New Scientist article I came across today.

A HIDDEN trap that detects how fast vehicles are going just by listening to them as they pass could catch speeding drivers unawares.

The system, being developed by the University of Tennessee and the Battelle Institute in Oak Ridge, uses microphones hidden by the roadside to measure the speed of passing vehicles. It does not emit telltale radiation, unlike radar or laser-based devices, so it cannot be picked up by dashboard detectors.
Click to expand...

New Scientist Article Link
 
It can't be purely sound based seeing as the sound of a car can be just as loud as a car doing 40mph in 2nd as 90mph in 4th. I call BS, plus the microphone would get vandalised? I know I'd accidently set fire to them all.
 
Violent-J said:
It can't be purely sound based seeing as the sound of a car can be just as loud as a car doing 40mph in 2nd as 90mph in 4th. I call BS, plus the microphone would get vandalised? I know I'd accidently set fire to them all.
Click to expand...

Uh, it's measuring the Doppler shift in the sound. Did you read the article?
 
fRostiE said:
just pull it out of gear once your satisfied your going fast enough :)
Click to expand...

I believe doppler shift would negate this also, it is looking for a change in pitch of any sound so I guess tyre noise would be the best thing to look for.



Doppler shift for retards:

Spitfire goes past at an airshow, you get the sound:

MEEEEEEEEEEEEEEOOOOOOOOOOOOOOWWWWW!

You determind speed by measuring the distance of the sound and the time it took to change through a pitch range and somthing to do with the speed of light resulting in a speed estimate. :)

Using this hideous bunch of maths:

http://en.wikipedia.org/wiki/Doppler_effect
 
Last edited:
William said:
I believe doppler shift would negate this also, it is looking for a change in pitch of any sound so I guess tyre noise would be the best thing to look for.
Click to expand...

bah :(:(:(

second thoughts, i can see a niche in the market ***SILENT TYRES***

brb im gonna phone a rubber supplier
 
A way to avoid the detection system using the doppler effect would be to create a "false noise".

I suppose you could disengage the clutch and start revving your engine. Although the doppler effect will still exist, the random changes in pitch, volume and placement may be too much for it to accurately calculate a speed.
 
They still wont catch the modders then.. i rarely hear their cars coming before i hear their subwoofer..
 
Technique after technique to catch people is all I see, most probably wont be put in place (at least I hope) but either way its pathetic.

Funniest one is restricting your speed by placing some sort of device in your car, imagine....a bunch of thugs chasing you to steal your car or someone bleeding to death. Oh I know, stay at 30mph so you dont break the limit....You know if you went through a scamra speeding to save a life they would still fine you lol ~ what a caring mafia I mean government!!
 
PMKeates said:
A way to avoid the detection system using the doppler effect would be to create a "false noise".

I suppose you could disengage the clutch and start revving your engine. Although the doppler effect will still exist, the random changes in pitch, volume and placement may be too much for it to accurately calculate a speed.
Click to expand...

Or you could just do the speed limit. That way you have nothing to fear.
 
I am guessing whoever is developing it has thought of all this, anyway you are travelling so fast over a unit which is at most about 2 feet square then any variation in pitch you make wont work. I doubt it will be implemented, it would be far cheaper just to camo up the exsisting cameras, I don't know why they havn't already.
 
How can this be accurate though. :confused: There is no way it will get the go ahead unless the gouverment just want to take all our points away and our money...

(knows this is what they are doing already.)
 
oweneades said:
Or you could just do the speed limit. That way you have nothing to fear.
Click to expand...

Apart from the obsessive enforcement of speed limits blinding people to the real causes of accidents and deaths on our roads, which only better driver standards and real police presence can address. Nothing to fear at all :rolleyes:

I don't suppose anyone actually did any further research than reading the sensationist article? This was original designed to measure the speed and weight loading of trucks by comparing the engine speed against turbo speed (the digital filtering can measure both). This technology is a bit of a non-starter IMO, you could be doing double the speed limit, but if you are slowing down as you pass the micrphone your recorded speed could be far lower, and vice versa.
 
Last edited:
oweneades said:
Or you could just do the speed limit. That way you have nothing to fear.
Click to expand...

There's a speed limit?

Well, I'll be.....I thought those signs were targets we had to beat. It all makes some kind of sense now.....
 
Trifid said:
How can this be accurate though. :confused: There is no way it will get the go ahead unless the gouverment just want to take all our points away and our money...

(knows this is what they are doing already.)
Click to expand...


For a start its in the states.
 
You must log in or register to reply here.
Back
Top Bottom