Washington, Simon P., Randall L. Guensler, Daniel Sperling (1993) Assessing the Emission Impacts of IVHS in an Uncertain Future. Institute of Transportation Studies, University of California, Davis, Presentation Series UCD-ITS-RP-93-19
To assess the emissions impacts likely to result from future implementation of intelligent vehicle and highway system (IVHS) concepts, requires making assumptions about the simultaneous emergence of technologies and policies. Emission characteristics of the future vehicle fleet, the penetration of electric vehicle technologies, and the impacts on driver behavior of future policies will have profound implications on research findings. This paper first summarizes the likely impacts of three IVHS technologies (advanced traffic management systems, advanced traveler information systems, and advanced vehicle control systems) given the characteristics of the existing vehicle fleet and current driving behavior. Then, each IVHS technology is revisited with changes in future assumptions – be they technology or policy based – to examine the potential air quality impacts. Assumptions about future conditions profoundly affect the expected air quality impacts of the three IVHS technologies. The emission reduction effectiveness of IVHS systems at the margin can be amplified or diminished by alternative assumptions, because projected trends in the vehicle fleet and transportation system characteristics can lead toward synergistic or competing air quality effects. Ongoing policy decisions currently evolve in an ad-hoc process, where new policies are based upon existing conditions and typically made in response to current politically-salient problems. Hence, the transportation system can evolve along multiple potential paths. In preparing transportation system analyses, the authors recommend that transportation planners and researchers consider the wide range of technologies and policies that may be implemented and note the synergism that may result from multiple strategy implementation. Furthermore, by examining the potential interactions of technology and policy decisions (i.e. by varying implementation assumptions) prior to making policy decisions, analytical results can be used to help develop rational-comprehensive transportation plans that provide more cost effective solutions to transportation problems.