The aim of the project is to investigate the modelled effects of four different road user charging systems upon an existing road network, using the congested assignment models SATURN and CONTRAM. Cambridge has been chosen as the most suitable study location, as the road network is considered to be of an appropriate size and structure for assessing the effects of charging and because it has been the subject of recent road user charging proposals. An existing SATURN model of Cambridge, provided by Cambridgeshire County Council, has been modified to suit the study requirements. In particular, existing trip patterns have been disaggregated into a series of separate user classes with differing values of time. The three main charging systems under consideration are toll cordons, the TIMEZONE time related charging system proposed for Richmond, the congestion metering system proposed in Cambridge. A structured series of tests is being carried out to reflect different systems and charge levels, and the effects which these may have upon the trip matrix. The effects of charges upon the frequency, timing and distribution of trips are being handled using the SATURN elastic assignment option, SATEASY, and an existing MOTORS strategic model for Cambridge. SATURN and CONTRAM is then being used to investigate the resulting network conditions. Results gained so far, for a toll cordon system, have revealed effects largely as expected, with increasing levels of charge leading to the diversion of traffic from the priced area and greater distances being travelled. Analysis of the total time spent travelling and average network speeds suggests that charges produce an improvement in overall network conditions up to a certain charge level, but may lead to deterioration beyond it. A range of results covering all the charging structures under consideration are available for presentation. (A) For the covering abstract see IRRD 863439.


  • English

Media Info

  • Features: References;
  • Pagination: p. 91-102

Subject/Index Terms

Filing Info

  • Accession Number: 00662289
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-86050-257-0
  • Files: ITRD, ATRI
  • Created Date: Jul 28 1994 12:00AM