volume of traffic measuring devices

[brian j john]

i asked this question a while ago but never got a definite answer and it is still a topic of discussion in my local , giving that there are two strips across the road can it measure the speed of the vehicle .

[Grunty]

One of the devices that has been used in the past to measure the speed of traffic consisted of two strips placed 27 inches apart on the road. Haven't seen it for years, and it has probably been replaced by the cameras. There is another device (unconnected as far as I know) that is used for counting vehicles. It doesn't know the difference between different types of vehicles, so you often see people in cars doing the counting.

[sddsddean]

Being 'in the business', the answer I gave you on the 11th October is definate. If you choose not to believe it, thats your problem.

[kempie]

Further to the answers in this and the previous thread, the two systems employed by UK police forces that use a similar system (DS2 and Speedmaster) require 3 strips or hoses to establish which direction the vehicle is travelling.

http://www.ukspeedtraps.co.uk/speed02.htm

[Grunty]

An interesting site Kempie. It does contain a few errors but I accept that the third element has been added in the short time since I last operated one (about 30 years). In those days we were not greedy and just covered one direction at a time.