Despite its success, London's congestion charge has few other cities rushing to follow its lead, reports Mark Hansford.
Congestion charging in the capital will be one year old on Saturday.
Without question it has been a success from a transport planning point of view - it has cut traffic, bus journey times are down, and bus patronage is up.
Questions remain over revenue (see box). But charging has been judged successful enough, at least in terms of pubic acceptance, for transport secretary Alistair Darling to make noises about some form of national scheme.
In giving the go-ahead for £7bn of motorway and trunk road widening schemes last summer, Darling committed to carrying out a feasibility study of road user charging. It was a significant announcement - the first time any government had admitted that there may be a better way than road tax and fuel duty to charge motorists for using Britain's roads.
Cynics point out that the government has admitted it will not meet its 10 year plan targets for congestion reduction, even though they were heftily revised in the 2002 update. Meanwhile, if engineers' fears are realised, cuts in roads spending are set to feature prominently in this summer's spending review. The maths are simple: there are more cars competing for road space.
Deterring drivers from using their cars at the same time as raising revenue to finance new projects must look attractive.
Whatever the government's true motivation, transport planners, lobbyists and motoring groups have raced to join the congestion charging study's steering group. This is now well established and will produce a progress report in time to feed into the summer review.
Work is being carried out strictly under wraps. The way findings are presented are calculated to either make or break any move towards charging. But it is understood a range of options are being modelled, from hi-tech satellite tracking systems down to simpler London-style camerabased systems.
'GPS seems attractive in terms of allowing charge variability but we're still considering other options, ' says Confederation of British Industry (CBI) business and environment director Michael Roberts, a member 'Satellite technology is not necessarily the only way, ' Motoring organisation the AA is a big advocate of a simpler solution. 'To start with, we have road pricing today - a 10p/mile tax paid on fuel, and annual road tax. At the moment we pay for what we use in a way that is incredibly convenient, very secure, and which for the government is easy to collect, ' says AA policy director John Dawson.
'The public at large has no problem with this system. So what we want is an evolution of it, ' he says. He argues that congestion is really only centred on central areas and main arterial routes. Congestion in centres can always be limited by permits, London style, and congestion on arterial routes limited by a differential road tax: Perhaps a different colour tax disk could identify motorists paying to use motorways at peak times. Enforcement would be simple, with cameras on slip roads. The technology is tried and tested, argues Dawson. His objection to satellite tracking is that it requires every vehicle to be fitted with a relatively expensive GPS transponder.
The Commission for Integrated Transport - not represented on the steering group - has long argued for satellite charging.
Satellite technology would in principle enable every road in the country to be assigned a charge, depending on the intensity of congestion. It would be near impossible to cover every road using fixed cameras.
But 'even if full scale road user charging with satellite tracking is chosen, the more interesting question is how do you get there?' says Transport 2000 executive director Stephen Joseph.
'You can't just switch it on.
Therefore there are some questions about transitions. Do you start with paying for lanes on motorways, then pay for motorways themselves. Or what about encouraging other cities to adopt London's approach?
'Can you make it so incredibly attractive for local authorities - stuff their mouths so full of gold - that they and their voters would be mad to turn it down?'
Other authorities have been slow to follow London's apparent success, with only Edinburgh vigorously pursuing a scheme. The Local Government Association (LGA) fears that many may have been put off by the possibility of a national scheme - how can any authority attempt to predict local traffic developments when huge changes nationally may be afoot? And how do you ensure your technology is compatible by that eventually chosen by Westminster. The LGA is now planning to produce its own report ahead of the national feasibility study to express these fears.
London: criteria for success
With traffic congestion in the capital now lower than at any stage since the mid 1980s, the success of the scheme in transport terms is unquestionable. Yet it still has many critics.
Tory candidate for London mayor Steve Norris says incumbent Ken Livingstone's scheme has 'undoubtedly damaged business'. If elected he has promised to carry out an immediate review.
But Livingstone's transport executive, Transport for London, disputes Norris' claim.
In its six month review of congestion charging it acknowledged that fewer people were coming into central London but claimed this was for a variety of reasons, pointing to a 7% year-on-year decline. It admitted that 70,000 fewer people are entering the zone compared to spring 2002, but said that since 85-90% of people coming into central London do so by public transport, the relative impact of reduced car use is minimal. It estimated that the congestion charging scheme is only responsible for around 5-7% of the overall reduction in people entering the zone. A Second Annual Monitoring Report due out in June will provide more detailed evidence on the impact on trade.
Norris has also been a vocal critic of the scheme's finances.
The scheme was expected to generate a net revenue of £120M in 2003/04 and £130M thereafter. Transport for London has cut this projection to £68M this year and £80M£100M in future years. The reduction is due mainly to the fall in traffic being greater than expected and some 'overestimation' of the base against which this fall took place.
Against this are balanced the running costs - estimated at £130M. On face value, London's congestion charge is operating at a significant loss.
But this, TfL argues, ignores the economic benefits derived from time savings and greater journey time reliability - it estimates these to be worth £180M.
Congestion and the 10 year plan cop-out
The government's 10 year plan sought to protect against projected growth in congestion. For the interroad urban network and in large urban areas the aim was to get congestion below 2000 levels by 2010.
But within two years, the message had changed. In its 2002 update the Department for Transport (DfT) quoted new forecasts suggesting that congestion will grow faster than previously assumed. These suggested that congestion levels on all roads in 2010 could be up 27%-32% without the 10 year plan, and by 11-20% even with it. On the strategic road network, a forecast growth of 52-67% without the plan was reduced to 1-15% with the plan. For large urban areas, growth of 25-30% without the plan would fall to 9-20% with it. These fears appear to be well founded. Traffic figures released by the DfT last week showed traffic levels rising by 1.4% in 2002-03, continuing an underlying growth rate of between 1% and 2% per annum since 1999.
Edinburgh sticks to its guns
A change of political control may have knocked Bristol out of the race, but Edinburgh remains committed to following London's lead.
Final amendments to its scheme were announced last month, taking the programme into a 28 day period for formal representations on the draft charging order that will be up for consideration at public inquiry. This starts in April.
The scheme consists of two cordons with a single daily charge of £2 for inbound journeys only.
The outer cordon will operate in the morning peak only so that people who live in Edinburgh but who drive to work outside the city will not have to pay to return home in the evening. Those living within the inner cordon will not be so lucky.
Meanwhile, Fife residents are angered at the prospect of a Forth Bridge 'double toll'. The principle of a concession to users paying both the Forth Road Bridge toll and the congestion charge is under review.
The scheme is expected to raise net revenues of £780M, with £430M spent on city based improvements and £350M regionally. City centre congestion is predicted to fall from 71% to 64% by 2011 and, across Edinburgh as a whole, from 26% to 17%.
Getting on the right track
On 9 July 2003 the Department for Transport document Managing our Roads announced the formation of a study to examine the feasibility of road user charging. A steering group will drive the study.
Clear objectives spell out the desire for a 'more efficient' approach to the structure of transport pricing that encourages economic growth, while ensuring that any system is fair, respects privacy, and promotes social inclusion and accessibility.
By June this year the study should offer up a set of possible charging regimes. It will have to assess the impact of each against a range of scenarios as well as congestion charging schemes already in place. It must look at the issue of confidentiality - would tracking impinge on individual privacy? It must address the robustness and adaptability of proposed technologies and the potential costs of introduction and operation. And it must come up with options and timetables for bringing forward charging to the point of full implementation.
In short, all the technical questions should be answered.
The decision on whether to proceed will then be a political one.