>>>>>Yeah, they're radar, aren't they, and work on the Doppler Effect principle. The hand-held, multi-directional ones are called, I think, Vascar.
>>>>
>>>>
>>>> Vascar has nothing to do with radar. It's a simple time vs distance measurement to determine speed.
>>>>
>>>>http://www.vascarplus.com/Pages/How_it_works.htm
>>>
>>>I always thought the hand-held "guns" that the UK police used were Vascar.
>>>
>>>While on the subject, do your police use a "breathalyser" to test DUI of alcohol - a gizmo that you blow into that registers the blood-alcohol level? Whenever I see progs like "The world's scariest police videsos" (or whatever), the troopers/traffic cops always seem to be farting around with the "sobriety test": standing on 1 leg, reciting the alphabet, walking a straight line, etc., but I never see the motorist blowing into anything.
>>
>>No personal experience, but I believe they do. The police usually don't go that far unless you can't pass the "field sobriety" test of normal functionality. The breathalyser usually comes after you've been arrested for suspicion of DUI, I'd presume.
>
>Strange - all that palarver when a simple blow into the m/c will give the result.
>Mind you, it makes good TV! :-)
>
>"... don't go that far"? - it's not as if the police draw a blood or urine sample at the scene! :-)

True enough, but I think it's still up to the cop's discretion to let you go on your way if you pass the field test. They're usually not the one to administer the breathalyser anyways, they call in a specialized unit in a mobile van. (at least they do here in Phoenix)
Once they do that, they're pretty much committed and your chances of getting off are greatly reduced.

>Mind you (again) it was possible to circumnavigate the results with the old system (where you blew into and inflated a bag, and turned crystals green if over the limit) by hyperventilating for c. 30 seconds prior. I've seen this done by a guy who was defo over the limit.

There's probably ways to beat it, but you're also not quite "thinking on all cylinders" under those circumstances.