blue cameras

[johnsealey]

what are the blue painted ,apparently empty ,structures pointing at the road on many bridges and intersections throughout uk?

[Ethel]

These are the traffic monitoring cameras used by tv and radio stations to give up to the minute traffic reports.

[sddsddean]

More or less. They are actually infra red or microwave (can't remember which) detectors for Trafficmaster to detect traffic speeds on the majority of the road network. This info is used by Trafficmaster to display jams/holdups on in car equipment and they also supply the info to various traffic organisations and radio stations.

[mr rusty]

You can often get a close look at them from footbridges where they are attached to the bridge- they are labelled as Trafficmaster and also as being specifically nothing to do with speeding, so itrate 9 or 10 point people don't trash them.

[buildersmate]

Yes, but do they just detect speed of a single vehicle passing, or are they (sometimes) organised in pairs to calculate the average speed of a vehicle along the route? I ask this because they appear to be organised in pairs on some (relatively-slow, single carriageway) A-roads, several miles apart. If the latter, they must have to capability to read number plates???

[kwicky]

http://www.trafficmaster.co.uk/page.cfm?key=RD S_TMC

[DrXXX]

They work by reading a vehicles number plate at one point and then read it again at the next point and work out the time it has taken you to travel between the two.
This enables them to see if traffic is flowing slow or fast on that stretch of road.
Could be usefull for tracking vehicles around the country.....but i am sure that does'nt happen !!!!!!

[maxi2]

They are there for TrafficMaster to measure traffic flow rates. They read only the centre part of registration numbers to do this - then ditch this data when it is used.