🚀 go-pugleaf

arnett@unixg.ubc.ca (Bill Arnett) writes:

>In article <schuck.720989040@sfu.ca> Bruce_Schuck@sfu.ca writes:
>>Some very interesting emissions research is being done in Colorado.
>>The professor who has done this research has also come up with a
>>gadget that can be set up on the road side to measure emissions of
>>cars going by. It uses a TV camera to record license plate #'s and is
>>relatively cheap. It is not as accurate as the Air Care type stations,
>>but that isn't important because the 2 out of 10 cars pollute much
>>more than the other 8.

>This sounds ludicrious to me.  How the heck is this device going to
>measure emissions quickly enough to photograph the offender?   It takes
>time for gases to travel to the sensor!  In my case the tail-pipe is
>on the left side of the car so the gases would have to travel 8 feet
>before they reached the sensor.  The car is going to be travel a *long*
>way before the gases reach the sensor.

The device does not sample the gases the traditional way.
As far as I know it measures the spectrum of the light passing from
one side of the gases to the other -- ie one piece on one side of a
lane of traffic and one piece on the other side.

>Besides this, wind direction, wind speed, and air turbulence would all
>have to factored in in order to decide which car produced the emissions
>and how dispersed the gases were by the time they got to the sensor.
>A certain error factor were be tolerable since an additional test would
>be performed, but I can't beleive that this could do much better than
>50% accuracy.

Even 50% aaccuracy -- I thinks its better -- would be adequate because
the goal is to get the worst offenders off the road. His figures were
something like 10% of the cars produce 90% of the pollution. That
means a really polluting car is produces 10 or more times as much
pollution as a relatively clean car. 50% accuracy is more than
adequate in this case. Who cars if you can measure the pollution of a
car to nth percentile. What we really want is the 1 or 2 cars out of
10 producing most of the pollution.


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"We've got to get bigger guns" -- Dick Durkin                  schuck@sfu.ca
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