Cameras behind gantry signs

[andygo]

I have meant to ask about this for a while, but has anyone any idea what the large camera things are that are situated behind most of the new signs that are on the M6 in particular.

These large electronic signs supported by a large concrete gantry situated on the n/side grass banking have been erected over the past couple of years or so. behind most of these signs sits a large camera usually with a bag over them.

I've not seen any signs actually working so what's the point?

[streaky]

andygo said:

I have meant to ask about this for a while, but has anyone any idea what the large camera things are that are situated behind most of the new signs that are on the M6 in particular. These large electronic signs supported by a large concrete gantry situated on the n/side grass banking have been erected over the past couple of years or so. behind most of these signs sits a large camera usually with a bag over them. I've not seen any signs actually working so what's the point?

The camera monitors traffic conditions, same as on M4 (see various threads here) - Streaky