Managing congestion, pollution, and pavement conditions in a dynamic transportation network model

Abstract

This paper presents a dynamic model that characterizes the changing states of traffic volumes, design capacities, and pavement conditions in a transportation network’s major commuting arteries. It also portrays the evolution of two system-wide effects—total vehicle miles travelled (VMT) and volatile organic compound (VOC) emissions—and accounts for lagged adjustments in travel behavior in its disequilibrium formulation. The model can be employed in optimal control exercises to determine what steps ought to be taken, when and where, and by how much in order to achieve planning objectives. Specifically, the model can be used to determine optimal combinations of traffic demand management measures, lane widening, and highway maintenance for achieving desired peak-period congestion levels, reducing VMT and VOC emissions to levels mandated by the Clean Air Act Amendments (CAAA), and keeping pavement conditions at acceptable serviceability ratings. Information on intertemporal tradeoffs between planning objectives, now required by the Intermodal Surface Transportation Efficiency Act (ISTEA), is generated in solutions to such exercises. We discuss how the model can be operationalized and illustrate its practicability with a small empirical example.