London's congestion charging scheme is only a few months old but already there are clear indications that it has achieved its primary objective, a significant reduction in traffic levels.
Rising levels of traffic in London were a cause of constant complaint through the 1990s. Driving a car through the central area took longer than the horse-drawn hansom cab of the pre-motoring era, it was claimed.
Levels of air pollution were rising. Health warnings were issued - certainly opening the car window on a sunny day as you crawled along a heavily used route left eyes watering and nose burning from the fumes. But when London mayor Ken Livingstone set out plans to charge anybody driving within the inner ring road ú5 ($8) a day there was consternation.
Various disaster scenarios were proposed, ranging from a complete collapse of trade within the central zone to gridlock in the streets just outside its boundary. In the event, none of these seems to have happened.
The charging zone covers an area of 21km 2. It operates north and south of the River Thames and embraces the West End with its theatres and famous shopping streets, plus the economic heart - the City of London. Altogether it accounts for 1.3% of the total area of Greater London.
There are 147 entry and exit points and these are all covered by cameras. Altogether there are 230 camera positions located both on the ring road and within the zone. Up to seven analogue cameras are mounted at each position. Colour cameras show the vehicle in its surroundings and monochrome cameras provide images of number plates.
This can be done accurately even in bumper to bumper traffic.
Both types of camera operate via a chip, a charged couple device and X-wave technology which allows better vision in poor light. Images are then sent via a purpose designed telecommunications system for automatic number plate recognition.
Here a data block which shows time and date for each image is checked against a database of those drivers who have either paid the charge or are exempt.
Drivers have up to 10pm to pay the charge, and until midnight with a $8 surcharge. The images of plates belonging to non-payers are manually checked against the DVLA database and penalty notices issued.
The charge operates Monday to Friday between 7am and 6.30pm. Disabled drivers, licensed taxis, registered minicabs and public service vehicles, motorbikes, mopeds and scooters are all exempt, as are emergency service vehicles.
Residents within the zone pay only 10% of the charge, and of those anyone driving a vehicle using alternative 'green' fuel is exempt.
When the scheme came into operation on 17 February the actual technology had been thoroughly tested, but there was an unexpected factor added to the travel mix. One of the principal underground routes was closed, and remained so for some weeks. Nonetheless traffic levels were down and more than 100,000 individuals had paid the charge.
From the first day and over subsequent weeks traffic levels have seen an average drop of 20% when compared with 2002 figures and it seems likely that this reduction, significantly greater than had been looked for, will be maintained.
Bus travel times have improved, delays have been reduced and buses are running closer to schedule. Most importantly, said a spokesman for Transport for London (TfL), bus use in London has, for the first time, risen to more than 5M passengers a day.
Other factors such as air quality are being closely monitored by TfL and these findings, plus a great deal more detailed information on journey times, traffic levels inside and on the perimeter of the central zone will appear in a report which is due to appear later this year.
The Association of Local Government is surveying the effect the charge is having on parking revenues in boroughs affected by the zone, and further surveys are being carried out on the impact on retail trade. It may be difficult to single out the effects of the charge from those of the general economic situation, weather, the coming and going of tourists, and a dozen other factors which affect people's shopping and leisure habits.
Despite initial problems with the issuing of penalty notices and the continuing hostility of some parties and sections of the press, boroughs on the periphery of the zone have indicated interest in its extension. Other cities both within and without the UK are looking to follow the London example.
'Hardly a week goes by without a visit by a group from a city somewhere which wants to study the scheme', said the TfL spokesman. 'I think we've presented to delegations from every continent except Africa and Antarctica.'
Perhaps the final word on the scheme so far belongs to a London taxi driver who remarked that a journey which had previously registered $17- $19 on the meter was now $11 - $13. 'But', he points out, 'the passenger is happier, he's more likely to jump into a cab if he thinks it will get him there more quickly, and I've got a better chance of picking up more fares. It's a win-win situation, gov'.