The US has started trials for distance-based charging mechanisms aimed at ultimately replacing the gasoline tax. Motorists in several US cities are being recruited to try out a new mileage-based road user charge system . The Public Policy Center of the University of Iowa is leading the trial. This is very good news (although I realise this trial is only the first step in a very long process with no gurantee of political success). Smart folks like Bern Grush and Robin Chase have been calling for usage-based pricing for a long time and pointing out that motor fuel taxes are gradually failing us. The Netherlands, Singapore and the UK apparently have plans for distance-based charging too. Germany and Switzerland already charge heavy vehicles based on distance and weight. There are spin-off opportunities here. I hope they don't get missed! It would be natural for people to be suspicious about having 'extras' that piggy-back on a new user charging system. But I think it would b...