A good idea, but would it work in practice? Inevitably, at some point in the future I think that the existing vehicle taxation system will be replaced by satellite-based road-user charging (prototypes are already being tested I believe) which charges according to how busy the roads are (ie. a higher charge for peak hour travel) and which could be configured for localised congestion charging schemes. Martin. [quoted text snipped - see the-hug.org/quoting.html]