It's official - you can reduce congestion without speeding journeys up, honest. Livingstone reveals the Holy Grail in this reply to Conservative leader Angie Bray:
Angie Bray: In section 1.2 (of the congestion charge annual report), it is stated that one of your key transport priorities is "to improve journey reliability for car users". Given that the average speed in the zone is now only 10mph, and that the report admits that the small gains made have been as a result of reduced queuing times, "rather than increases in driving speeds", is this priority being met?
Ken Livingstone: Congestion in urban areas is mainly in the form of queues at junctions. It is this that mainly determines journey time reliability, rather than actual driving speeds per se. Therefore, TfL's congestion charging targets precisely that element of delay that contributes most to unreliable journeys.