Multiclass Traffic Assignment Problem with Flow-Dependent Passenger Car Equivalent Value of Trucks

Abstract

This paper develops and analyzes a multiclass traffic assignment model considering the flow-dependent passenger car equivalent (PCE) value of trucks based on the latest Highway Capacity Manual (HCM, 6th edition) and explores the properties of the proposed model to provide guidance on related planning applications. HCM discrete values of truck PCEs are fitted by power functions for combinations of link grades and lengths, which have been found to produce high coefficients of determination ( R2) in all cases. With the established fitting functions, the multiclass traffic assignment problem is formulated as a variational inequality problem and solved by an efficient method. The equilibrium link flow distribution is proved to exist but may not be unique. Numerical examples and discussions are presented to demonstrate the variance of the link flow distributions and the effect of such nonuniqueness on traffic planning applications. Several approaches are then provided to obtain the best range of solutions according to a congestion pricing design problem.