Cost of Driving Comfort and Convenience for Two‐Lane Highways

Abstract

Described in this paper is the development and calibration of a proposed model for estimating the cost of comfort and convenience related to driving on two‐lane highways. The starting point for the model presented here was an earlier study which showed that the traditional cost factors and variables, when employed with the 1985 Highway Capacity Manual's revised data and procedures for two‐lane highways, could underestimate the user cost and reflect inappropriately the deterioration of user service with an increase in the volume of traffic. Based on several past studies, the proposed model for the cost of comfort and convenience considers such factors as the relative importance of driving comfort as perceived by road users, the unsatisfied overtaking demand, “percent time delay” curves, the type of road use, volume‐to‐capacity ratio, the desired highway speed, and vehicle classification. The paper describes and discusses in detail the concept and estimation of the model parameters. The model parameters are estimated by considering the shape of generally accepted cost versus volume‐to‐capacity ratio curves and the current practice of planning and design of highways.