Maximum speed

[neddyw]

A lot of bends near us have been resurfaced with anti skid tarmac and signs have been put under the 'bends' signs. They are square and say 'maximum speed 20mph'. Is this a recommended speed or a mandatory speed limit? I thought round signs were instructions and other shapes were warnings or information?

[sddsddean]

Although they look as though they are mandatory, they are almost certainly advisory. A mandatory sign must be the recognised shape (red circle, white ground, black number), but they also have to be 'put into force' (sorry, my memory is failing and I can't remember the proper term!). This means they at least must be made legal by the local authority. In the case of anti skid, the advisory is there as it is like driving on marbles when the stuff is first laid and it takes a bit of time to 'bed in' and for the excess to be swept away.