Safe Speed Forums

I came across this:

http://www.ukspeedtraps.co.uk/laserpropark.htm

Apparently it's a parking distance device that has the side effect of interfering with laser speed meters.

The legislation intended to ban laser jammers isn't even agreed yet and already it's in trouble.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

I'm surprised no one has adapted the parking sensors so that they could be used as a distance check to make sure you weren't driving too close to the vehicle in front. That would be a real useful safety device.

I have been gap checking when I've been out and about and discovered the gaps aren't as big as I thought... usually around 3 seconds at 30 but often only 2 seconds at 40 mph areas for some reason. I always left much bigger gaps when I was less experienced but for some reason I have drifted into sitting a bit too close sometimes without really being aware of it. I also find I sit in the shorter following distance behind piddlers on nsl roads rather than in the well back position when someone is getting a reasonable move on (another reason 40 mph piddlers are dangerous perhaps? )

Worryingly even when I know I have been driving a bit too close most of the other vehicles around are driving even closer

Would be a neat idea for this device - if it works as a genuine parking sensor then it shouldn't be difficult to do.

As for the legality, the Road Safety Bill is enabling the ban of devices of which "the purpose or one of the purposes" is to detect or interfere with a speed assessment device. Unless they are marketed with absolutely no reference to the ability to interfere with a laser gun then I have no doubt they will fall under any ban, and even if they are marketed properly then they could still be liable. The risk of a prosecution for obstruction/attempting to pervert the course of justice is also there.

Gareth

I have posted my opinions regarding this type of device on PH in the past, no-one really responded. I’ll post again here, to an audience who I believe will have a better understanding.

Unlike radar detectors, these devices do not detect the presence of a carrier; they instead modify the pulse train received by the gun. Hence I don’t believe the radar case (legal because the carrier is only ‘detected’) can be used as precedent.

I think it's clever that these units are marketed as self-triggered door openers, but if these behave differently when triggered by a lidar gun (i.e. transmits a different pulse train or gives any specific warnings) then it would be viewed as ‘acting upon the information’ transmitted from the gun.

I really worry about the risk arising from the use of dual function jammers. There is a substantial performance difference between a genuine garage door opener (or rangefinder) and a jammer. It is reasonable to expect that a genuine door opener can detect the collimated high power pulses from a lidar gun, even from great distances. However, IMprofessionalO a genuine door opener won’t be able to jam a lidar gun. A rangefinder could only if aimed directly at the lidar gun. A genuine door opener (or rangefinder) needs little output power; they need only work for up to 20 meters (or at a very small divergence); hence they’re unlikely to be able to affect the operation of a Lidar gun at useful distances. Conversely, a jammer must cover a large surface area hundreds of meters away (inverse square law), with received pulse intensities at the gun comparable to those reflected from a retro-reflective VRM; therefore needing to output lots of power. I reckon a good prosecutor could secure a conviction within existing laws, demonstrating wilful intent of interfering with the speed measuring equipment, based on that simple technical premise. This can easily be proven - by the likes of say, me!
There is also the issue of eye safety. Some jammers use a class 1 laser which isn’t up to the job of jamming at useful distances for the reasons given (I guess this is why LEDs are sometimes used as these are not subject to the same power regulations).


LTI Lidar speed meters have been designed to be able to detect and reject noise emanating from, for example, such countermeasures. From what I can deduce from some brief surfing, jammers end up generating many error codes on the LTI, but not the usual E03. This could be enough for a seasoned operator to become suspicious. The driver could be pulled for suspicion of jamming, even if not speeding. A quick examination of the car would certainly result with a summons; no sensible plod will fall for ‘that is a door opener’ excuse. Even if a jammed speed meter didn’t generate error messages (and a speed wasn’t displayed) it could be enough to prompt the operator to flag the car on their database. The car may be subjected to a late night examination if that user accumulated too many of these flags.


You’ve been warned. Use them at your own risk! I certainly won’t be risking it.
A device that can fool lidar guns, now that’s a different matter…………

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

I suspect you'd find that the actual sensors currently in use would only operate reliably at up to a couple of metres range.

And even if you replaced them with some more far-sighted one you'd presumably have to play around a fair bit to get sufficient divergence to acquire the car you are following but without falsely picking up returns from the road, especially when going over bumpy roads.

It would be interesting to see if it could be made up into a useful "Safe Distance" gauge, that reads current speed (perhaps via GPS), integrates this into a two second gap and then makes this the centre point on the gauge.

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CSCP Latin for beginners...
Ticketo ergo sum : I scam therefore I am!

ACC does all the above.... in its electronic head.. but then it would cost as much as ACC to add the hardware.

Like a motorbike?

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Andrew.

isn't this essentially what Mercedes have done with their active cruise control or whatever it's called? What I'd like to know is how it works out the amount of available traction - ie does it leave bigger gaps in rain/snow?

yes ACC....
it doesnt know anything about traction, the driver sets max speed and 'headway' (following time).

oops, sorry abou that. I must be going blind, I didn't even see your post...

..although there are collision mitigation & collision avoidance systems in development which presumeably have to make an appropriate guess at the level of grip before firing off.

IN OLDIES CALLED "OBSERVATION, AND EYESIGHT"

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lets bring sanity back to speed limits.
Drivers are like donkeys -they respond best to a carrot, not a stick .Road safety experts are like Asses - best kept covered up ,or sat on

Botach, surely you don't mean the Mk I eyeball ???

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Chaos, panic and disorder - my work here is done.

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