Those who are already worried about Alistair Darling’s controversial road pricing scheme should be positively fearful, if Germany’s experience of GPS-based road pricing for trucks is anything to go by.
Problems with the Toll Collect system have been many, ranging from the usual delayed start and cost overruns of big public sector IT projects, through to embarrassing engineering miscalculations. Sin-bin lay-bys built to hold trucks stopped for non-payment were designed with an optimistic idea of how quickly computers could capture a number plate and check a central database. Once in action, this meant that the lay-bys were too close to the gantries containing all the cameras and computers - guilty trucks had gone by before anyone could tell if they should be stopped. Moving the gantries or lay-bys would be costly, so the politicians' solution was adopted: the traffic was slowed down to keep pace with the computers.
Worse, when problems of inconsistent billing became obvious, the German government rushed through a law under which Toll Collect never has to prove that it has charged the correct toll - instead it’s up to the victim to demonstrate that they have been charged the wrong amount.