Ubiquitous ANPR surveillance

I knew that ANPR was already used by police to give details of cars, and in the average speed motorway cameras to track individual vehicles' speeds, but I had no idea how widely it was used locally until I walked past this sign in Aylesbury and read it closely.

This leads me to a couple of questions...

Are the blue-shrouded cameras on major roads, which I always imagined tracked speed by some sort of detection of a vehicle's speed, actually a network of ANPR devices, and is it these to which this sign refers?

When I look at the traffic layer (either live or average historic) in something like Google Maps, is all any, some or all of this data being generated by ANPR data sources?

Suddenly, I feel the need to walk and take public transport a whole lot more.