London mayor Boris Johnson’s pledge to improve traffic journey times by means other than congestion charging was given a boost by the finding that delays have returned to pre-charging levels.

Delays in the London congestion zone boost Johnson's alternative plans.

Johnson pledged to ‘accelerate the delivery of plans to improve traffic flow,’ as Transport for London reported that congestion within the charging zone had returned to 2002 levels, and the western extension had provided ‘no congestion relief’.

He expects TfL to provide proposals for re-phasing traffic signals to smooth flows by the autumn, and wants the London street works permit scheme to be up and running by March.

TfL’s acknowledgement that its reallocation of road space was a factor behind the increase in congestion within the charging zone – after reductions of 20-30% each year until 2006 – also gave Johnson an apparent boost.

TfL said road-space reallocation, such as major public realm projects and ‘all green’ traffic signal phases for pedestrians, was partly responsible for increasing congestion.

Johnson has abandoned his predecessor’s scheme to partly pedestrianise Parliament Square. It also emerged this week that he is to end Ken Livingstone’s ‘100 public spaces’ project, which includes 13 proposals for new or remodelled spaces.

However, TfL’s analysis was that the single biggest cause of congestion in the western extension was a private-sector development which had halved the capacity of the junction of Sloane Square and the Brompton Road.

The replacement of water and gas pipes was another main reason for congestion creeping up, it maintained. In the case of Thames Water, Johnson has pledged to tackle jams, in the short term, by encouraging the covering of excavations with steel plates.

TfL also identified an increase in the number of buses as being another contributory factor, which is a blow to Johnson’s plans to replace articulated buses.

Joe Weiss, chairman of the London Technical Advisors Group, warned that providing a Routemaster-style double-decker, providing half the passenger capacity of a ‘bendy bus,’ while maintaining bus capacity, would further reduce road space.

‘We are running out of surface capacity,’ he said. The prospect of public space schemes being revised or scrapped was news to London boroughs.

Greenwich council said it had had ‘no communication from the mayor’ about the planned Woolwich town centre scheme. A spokesman for the mayor promised a new public space strategy with ‘a greater focus on delivery’ to replace Livingstone’s ‘highly-aspirational’ programme which had delivered five schemes in eight years.

He also pledged that signals would be re-phased ‘without prejudice to the needs of pedestrians’.