There are sign saying the same thing around J1 and 2 of the M5.
I'm also convinced that the so called 'smart motorway' speeds are based on a clockwork device in the control room as they seem to go on and off on a time basis irrespective of the traffic.
They also assume I need 5 miles or so to slow down when there is non-existent 'debris in the road'.

They are nothing more that a feeble attempt to increase capacity 'on the cheap' and yet they are not so cheap. RRS HSE Dynamic SDV6 2014

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