Interesting debate but not for this forum. Moving to Non Air Transport issues if you want to continue it.
As a matter of interest if you want to identify the different types of surveillance on the roads and which are used by the authorities for revenue generation and which (by the sound of the blue poles mentioned above) are used by the likes of TrafficMaster to compute traffic flows have a look at
The Speedtrap Bible which has a section on just about anything to do with speeding.
Specifically these:
Read this:
http://www.brakehorsepower.com/speed..._notatrap.html
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Capt PPRuNe aka Danny Fyne
The Professional Pilots RUmour NEtwork
[This message has been edited by Capt PPRuNe (edited 27 April 2001).]