Supply Models for Use in Modelling the Variability of Journey Times on the Highway Network
J Bates, John Bates Services; I Black, Cranfield University;
This paper will report the outcome of a project for DfT, which forms part of its ongoing research programme on journey time variability (JTV). This research is currently evaluating alternative frameworks for supply models of JTV, including models which consider incident related variability separately from other sources of variability.
The paper will also review alternative methods for incorporating the uncertainty of travel time into utility functions. Consideration will be given to the need to reconcile measured and perceived versions of JTV and the practicality of avoiding an incidents/events segmentation, which depends on arbitrary definitions. Existing models including the INCIBEN/INCA models developed earlier in the ITEA research programme, and an incident variability model described by Cohen & Southworth will be evaluated. Finally, the paper will develop generic models of JTV and consider the detailed problems faced in using automatic number plate recognition (ANPR) data collected on UK motorways to calibrate such models.
Association for European Transport