§ Mr. Jamieson
I have asked the Chief Executive of the Highways Agency to write to the hon. Member.
Letter from Tim Matthews to Mr. David Laws, dated 25 March 2003:I have been asked by David Jamieson to reply to your recent Parliamentary Question asking him to list the ten stretches of motorways in England experiencing the most congestion.The Department for Transport and the Highways Agency uses long-established modelling techniques to assess road network congestion, and to forecast future congestion depending upon a range of traffic growth and transport infrastructure investment assumptions. A traditional output of this work is a three-banded "stress map" indicating those parts of the network that are experiencing peak and off-peak congestion. The latest available version of the map estimating the effect of congestion was published in the Ten Year Plan for Transport.This modelling method is not designed to rank individual motorway links within the congestion bandings. To obtain a measure of congestion on individual motorway links consistent with most congestion indicators, it would be necessary to measure journey times and speeds as they vary hour-by-hour and day-by-day. Regular network-wide measurement of journey times at this level of detail has not been carried out in the past, mainly because of the extremely high costs that would be involved. However, the opening of the Traffic Control Centre next year will greatly improve our knowledge of traffic conditions and will lead to comprehensive information on journey times and speeds being made generally available to the travelling public.