§ Ms. RuddockTo ask the Secretary of State for Transport what research has been conducted by his Department into the effects on traffic congestion of building new roads or widening existing roads; and if he will ensure that such research is placed in the Library.
§ Mr. ChopeThe effects on traffic congestion of building new roads or widening existing roads are a major element in the traffic and economic appraisals carried out by the Department for all improvements to trunk roads. The Department's methods of traffic and economic appraisal have been developed over many years, based on a continuing and substantial programme of research projects.
In the traffic and economic appraisal of road schemes, the effect on traffic flows, queues and speeds are estimated first; these are then valued through the time savings to business and private road users and the improved productivity of commercial vehicles. For schemes in the current roads programme, on average, the present value of benefits, discounted at 8 per cent., is 2.4 times the present value of costs.
§ Ms. RuddockTo ask the Secretary of State for Transport what research has been done by his Department 347W into the savings on emissions from a reduction in congestion; and if he will publish the modelling and methodolgy used to calculate the relationship between emissions and traffic congestion.
§ Mr. ChopeThe research evidence on road transport emissions of greenhouse gases is summarised in TRRL contractor report No. 223, "UK road transports contribution to greenhouse gases: a review of TRRL and other research", a copy of which has been placed in the Library. To predict the impact of individual schemes on congestion, the Department makes use of detailed traffic simulation models. The models make use of information on road link and junction characteristics to predict vehicle flows and speeds which can in turn be used to estimate fuel consumption and emissions. The Department has a substantial programme of research into this and other environmental issues.