Energy-based fuel consumption model for FREFLO

CORFLO is a strong tool for evaluating coordinated freeway corridor traffic management strategies because of its capability of explicitly simulating freeways and surface streets within a single environment. The lack of a fuel consumption estimation capability in FREFLO, the freeway simulation component of CORFLO, however, limits its application for evaluating corridor management strategies directed at the much needed conservation of scarce petroleum resources. The objective was to develop and implement a fuel consumption model based on the most currently available fuel consumption data. A review of previous work on fuel consumption modeling indicated that a model based on the energy consumed to overcome the forces resisting a vehicle's motion is suitable for implementation in FREFLO. The relation between acceleration noise and density was used to estimate the acceleration owing to vehicle interaction. The model was calibrated by using fuel consumption data obtained from FHWA; these data are representative for 64% of the passenger vehicle fleet from 1980 to 1992. The model explains 99.5% of the variation in the constant-speed fuel consumption data and 86.1% of the variation in fuel consumption due to acceleration. Air drag and rolling friction coefficients computed from the model parameters were near the lower bounds of the range of theoretically possible values. The fuel consumption estimates obtained from FREFLO and INTRAS for a small segment of I-35 near Austin, Texas, were comparable under most traffic conditions.