[sci.electronics] VASCAR

little_re@lrc.uucp (02/19/91)

>>VASCAR, eh?  I haven't heard of this in years.  Didn't know it was still being
>>used!  Wasn't there a problem with having to make a subjective judgement of
>>when the target car and the police car passed the same point?
> 	When the specific car passes the first line, a stopwatch is activated.
> 	When the car passes the second line, that stopwatch is stopped.
> 	Since the cop has your distance travelled and the time it took you
> 	to travel that distance - he has your speed. Very accurate, too.
> 	In that particular feature, the actual "detector" was in the
> 	plane and they had a few officers down the road to pull off the
> 	"offending" cars...
> 	P.S. In some states (or even locations) they VASCAR unit is inside
> 	a car, instead of a plane. Some even have sensors in the
> 	road itself and the computer (I presume) alerts the cops that
> 	a car (or group) is going faster than the limit. 

   I definitely know about how VASCAR works.  I was the one that was pulled
with it.  The "detector" if you will, was inside the Ford LTD and the marks
on the road were 2/10 of a mile apart.  I know because I asked the cop that
pulled me.  I asked another highway patolman how it works and he told me that
the cop either triggers the unit to start or there is some sort of light beam.
I think in my case it was the cop that triggered it.  Inside the unit, once
it is turned off after the distance is recorded, calculates the speed.  Neat
idea, just too bad it was used on me!


			Rich Little
			Lenoir-Rhyne College
			Hickory, NC

whitten@kuhub.cc.ukans.edu (02/21/91)

>>>VASCAR, eh?  I haven't heard of this in years.  Didn't know it was still being
>>>used!  Wasn't there a problem with having to make a subjective judgement of
>>>when the target car and the police car passed the same point?
>> 	When the specific car passes the first line, a stopwatch is activated.
>> 	When the car passes the second line, that stopwatch is stopped.
>> 	Since the cop has your distance travelled and the time it took you
>> 	to travel that distance - he has your speed. Very accurate, too.

The plane version of this setup, as the television version of motorweek
pointed out the other day is quite accurate.  Using a 1/2 mile stretch
of road, a full 1 second error on starting or stopping the clock from
the plane results in something like less than 2 mph error.  Atleast as
accurate as some highway patrol with a miscalibrated radar, and a bad
aim.
 
Regards,
Chris


==============================================================================
 WHITTEN@KUHUB.CC.UKANS.EDU              Chris Whittenburg, Univ. of Kansas
 WHITTEN@UKANVAX.bitnet                        Electrical Engineering
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