Route guidance and information systems

Abstract

This paper reviews key aspects of route guidance and information systems (RGISs), which disseminate to drivers messages with information and recommendations intended to assist their route choice decisions. It first summarizes the major features that characterize and distinguish different RGIS designs. An important distinction exists between non-predictive and predictive systems. In the former, guidance messages are based on measurements or estimates of prevailing network conditions, while, in the latter, messages are derived from forecasts of future conditions. For predictive systems, the key issue is consistency: ensuring that drivers’ reactions to guidance derived from forecasts do not invalidate those forecasts. It is shown that the determination of consistent guidance must be model based and can be formulated as a fixed-point problem. The modelling of driver response to guidance is a relatively new subject; the paper surveys the main issues, and relates these to the user-and system-level evaluation of RGISs. A final section identifies some areas of current research.