Route guidance information systems have the potential of reducing or eliminating poor route choices and consequently excess travel time and cost incurred by unaware or uninformed drivers. When drivers with communication devices receive public information and alter their behaviour, they affect driving conditions for others, both those with devices and those without. Moreover, if uninformed drivers know that informed drivers are out there, they may also adjust their behaviour, albeit on a routine rather than daily basis because they lack day-specific information (Arnott et al. 1990). This may cause informed drivers to make further adjustments, and so on. Thus, the reliability of the route guidance information systems are endogenously determined by all drivers’ behaviour within urban networks. A driver’s behaviour changes over time, often from day-to-day, due to learning, expectations formation, variable perception of the reliability of the information received, etc. Thus, in broad terms, any framework aimed at analysing the potential impact of route guidance information systems should incorporate dynamic models of drivers’ behaviour and expectations formation.