§ Mrs. Dunwoody
To ask the Secretary of State for Transport what estimate his Department has made of the cost of traffic congestion to British industry in each of the last 10 years. 
§ Mr. Norris
The Department has not made estimates of the total cost of traffic congestion to British industry. At a national level, such costs are very difficult to identify. Others have made estimates of the cost of congestion in this country on the basis of work carried out by the Organisation for Economic Co-operation and Development some six years ago. However, the method used contains a number of gross simplifications and the results are consequently unreliable.
Our own assessments have focused on the appraisal of individual transport projects. They start from the baseline of current conditions and estimate the reduction in costs in the area concerned that can be achieved by implementing the project. These estimates are based on an extensive body of research findings.