Take the results TfL have published about the removal of the Western Extension of the Congestion Charging Zone (WECC).
Bristol, which was originally enthusiastic about congestion charging, dropped its plans when the Liberal Democrats took control of the council.
ECONOMIST: Can road pricing spread beyond London? Not without a push
The Tories are also opposed to both urban and inter-urban congestion charging, even though the last Conservative government proposed tolls on motorways.
David Hughes-Lewis of Cardiff Retail Partnership said congestion charging was "almost inevitable".
London is one of only a handful of cities with congestion charging.
Still, if congestion charging can work anywhere, London is probably the place.
Mr Green says the RUA does not oppose road congestion charging but believes it must be fair, reasonable and not just another tax.
He says that if the problems of congestion are to be tackled, there will have to be a switch from fuel duties to congestion charging.
Ministers know they need to switch the burden of tax from fuel to direct charges such as motorway tolls or urban congestion charging, but fear voters' reaction.
And Mr Livingstone can claim a mandate to try congestion charging: it was part of his pitch to the voters before he was elected two years ago.
More than 75% were opposed to congestion charging if the money went to the Treasury, but 71% were in favour if the money raised was devoted to transport.
She said the Public Carriage Office and congestion charging unit made regular checks on licensed vehicles to "ensure they are being used for the purposes for which they were licensed".
Mr Livingstone says his other key ambition as mayor, apart from congestion charging, is to reassure Mr Blair that it is sensible to decentralise power and to move towards regional government.
The most recent annual report on congestion charging, a report the London authorities are required to produce, says that the practice has resulted in a 16% reduction in road traffic CO2 emissions in the (original) charging area compared to average 2002 levels.
Whether you are looking at London leading on congestion charging, or San Francisco leading on solar power (with a system the size of a football field on top of its convention centre), it is clear that strong civic leadership matters most of all.
Plans for a road-pricing scheme in a heavily used bit of the Peak District National Park, in Derbyshire, are on hold, as is a congestion-charging scheme in Cardiff, and a planned workplace parking levy broadly the same thing in Nottingham.
ECONOMIST: Can road pricing spread beyond London? Not without a push
But deterring congestion will in many cases require charging more than the marginal social cost of motoring, and this will impose economic loss on society instead of stemming it.
Diplomats were settling congestion fee bills but now their offices are inside the charging zone, they have stopped paying.
BBC: NEWS | UK | England | London | Embassies suspend paying C-charge
Despite the worries of some newspapers and motoring organisations, the government still hasn't adopted Road User Charging as its policy for tackling growing levels of congestion.
Notably, spending could be substantially lower if demand for highway travel was reduced by charging fees to highway users that reflected the costs they impose on others when they drive during periods of congestion.
Some of the benefits are well-known, such as the lack of Vehicle Excise Duty and exemption from the London congestion charge, but it's becoming easier to charge up a Nissan LEAF on the move with more public charging points opening all the time.
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