Ok they are using the excuse of polution, so if some one has an electric car they are still restricted, i just wonder how much monies they have brought in by the camara system, if a car runs most efficiantly at 50 mph then why not have all roads at that speed, of course it will not be safe to travel that fast on all roads and lower restrictions are needed many parts of London have a Maximum speed limit of twenty MPH polution wise slow speeds are far from efficiant as far as polution. what is not taken into account is time, and time cost money. there is also the argument that fatiuge and frustration can also make drivers to lack concentration although less serious accidents happen there are more of them. the results in America when al planes had been grounded had supprised most people of the change in pollution levals.