What on earth are variable limits designed to achieve...?
Surely not just collect money?
Thank goodness, other than on the Motorways, where they do seem to help a bit, we don't seem to have discovered this "fascinating" concept.
Variable speed limits are specifically designed to break up the standing waves you get with large volumes of traffic on roads with no natural breaks. Slowing down parts of the flow intermittently breaks up the waves and permits more constant throughput.
Variable speed limits aren't used off motorways because they aren't needed.
