Incorporating traveler response to pricing policies in comprehensive activity-based models of transport demand

The growing number of studies and continued policy interest in road pricing strategies and technologies represent new challenges to transportation researchers in their attempt to better understand and predict the impact of various pricing strategies on travel behavior. We contend that these policies and associated modeling approaches should ideally be embedded in the next generation of comprehensive models of transport demand: dynamic activity-based models. This statement is based on the fact that these pricing strategies are implemented to induce behavioral change. To the extent that these policies are successful, such behavioral change potentially involves both primary and secondary changes in the strongly linked set of choice facets that make up comprehensive activity-travel patterns. For several decades, the basic form of the travel demand model was known as the "four stage travel demand model. Generally, it relies on data and model development supporting a local jurisdiction's long-range plan. But to adequately forecast traffic and revenues or to analyze the effect of pricing policies, the model system must be sensitive to the effects of these policies on both travel behavior and land use. This is where the new generation of activity-based transport demand models provides most information for road pricing analyses. Activity-based models and micro-simulation modeling techniques distinguish the new generation models from the conventional four-step model. To assess the state-of-the art, a literature review was conducted to examine to what extent the current state-of-the art meets this ambition. This paper reports the findings of this state-of-the-art review of road pricing analysis and travel demand modeling. Based on this, limitations are identified and several needs for future research are suggested