As Simon Jenkins says:
"Merely raising petrol duty, a general mobility tax, is nowadays seen as too crude. Opposition to satellite tracking is fierce and understandable, especially when proposed by a government with so little concern for civil liberties (and so inept at computing)."
How seriously has the government examined alternatives, both technological (such as the anonymous prepaid toll cards of Singapore) and the simpler and cheaper taxation of city centre parking spaces? Instead, the Department for Transport is considering "voluntary" satellite tracking trials.
A "mobility tax" in the form of increased fuel duty may be less equitable, but it is the only way to tackle the climate change (as opposed to congestion) impact of increased driving.