The surge of road pricing projects in the U.S. and around the globe over the past fifteen years has been enabled by a set of new communication and transportation technologies. There is currently a wide array of technical configurations ranging from systems based on “tried and true” short-range radio communications to experimental systems relying on global positioning satellites. These technologies provide for a more efficient collection of simple tolls, and also facilitate a movement toward more dynamic, variable user fees.
In this study, we provide a comprehensive literature review of eight road pricing cases to identify types of tolling technologies employed, given various policy objectives. In particular, we examine two examples from each of four types of road pricing programs: 1) facility congestion tolls, 2) cordon tolls, 3) weight-distance truck tolls, and 4) distance-based user fees. In the selected cases, we specifically examine various suites of technologies and evaluate approaches to their implementation in road pricing programs with regards to system design and policy.
In our literature review, we first describe three major technical tasks to be performed—metering road use, calculating charges, and communicating data—that are implemented by a set of nine technologies varying from on-board units to global navigation system satellites. Secondly, we identify six primary policy goals of these road pricing systems: a) maximize underutilized capacity, b) offer a congestion-free alternative, c) generate revenue, d) reduce congestion, e) allocate costs to users, and f) develop a user-fee alternative to the fuel tax.
In our careful synthesis of the literature, we find that two main policy decisions most often determine the selection of roadway tolling technologies: (1) the geographical scale of the road network tolled, and (2) the complexity of calculating the fee to be charged. The combination of these two factors can vary greatly – from tolling individual facilities with flat fees, to nationwide road networks priced with dynamic tolls that vary by vehicle class, time of day, and congestion level. Taking into account the severe funding shortfall for transportation infrastructure, serious concerns about traffic congestion, and related adverse environmental impacts, we expect electronic road pricing systems to continue to grow in scale as well as in number. While systems with newer technologies are continuously in development, the most difficult hurdle for road pricing programs is now less of technical feasibility, but rather political and public support for implementation.