I'm not totally convinced of the need for a lower limit. I think there are other road safety measures that need to be enforced - like stamping down on white van men. I was almost knocked down by one the other day as he drove at me along the pavement. When I kicked his van and called him a silly billy :), he stopped, got out and threatened to punch my head in - until I took a video on my phone of him and his van on the pavement and told him I was reporting him to the police.

At least I learned some nice new swear words.