Energy and Environmental Impacts of Roadway Grades

Abstract

Although roadway grades are known to affect vehicle fuel consumption and emissions rates, there do not appear to be any systematic evaluations of these impacts in the literature. Consequently, this paper addresses this void by offering a systematic analysis of the impact of roadway grades on vehicle fuel consumption and emissions rates by using the INTEGRATION microscopic traffic simulation software. The energy and emissions impacts are quantified for various cruising speeds, under stop-and-go conditions, and for various traffic signal control scenarios. The study demonstrates that the impact of roadway grade is significant, with increases in vehicle fuel consumption and emissions rates in excess of 9% for a 1% increase in roadway grade. Consequently, a reduction in roadway grades in the range of 1% can offer savings that are equivalent to those offered by various advanced traffic management systems.