A Rational Framework for Determination of Tariff Rates for Overweight Trucks

摘要

This paper presents a rational approach for determination of permit fees for truck traffic based on consumption of service life of highways. The prescribed approach uses mechanistic-empirical design philosophy for estimation of deterioration of the pavement structure. The methodology uses permanent deformation, load-related fatigue damage, and roughness scores as primary descriptors for estimation of the service life consumption. The experiment factorial included flexible pavement sections with varying structural numbers and sampled across Texas to account for climatic and geographical differences. Each of the pavement sections were simulated under different loading conditions to reflect the full spectrum of axle weights that are characteristic of single, tandem, tridem, and quad axles. The aforementioned exercise provided the basis for developing the group equivalency (GEF) and axle load factors (ALF) for individual axle groups. The determination of axle specific parameters enabled adoption of a modular approach towards determination of gross load equivalencies for any truck category without any restriction on axle weights or configuration. The consumption of the service life was calculated as the additional pavement structure that would be required to accommodate traffic in excess of the design truck volume. The cost incurred in the process of providing the additional structure was assigned to the responsible truck fleet in proportion to the marginal load equivalency over the legal gross vehicle weight (GVW) and axle weight tolerances. Results indicate that a permit fee of 3.7 c/mile/ESAL is equitable based on the findings from this study.