Effects of Pavement Condition on LCCA User Costs

Life cycle cost analysis (LCCA) is one of the well-established methods to determine the cost-effective alternative between different transportation infrastructure projects. Life cycle cost of a roadway alternative consists of agency and user costs over an analysis period appropriately selected. Agency costs include initial construction costs, and maintenance and rehabilitation costs incurred within the analysis period. User costs incur when there is a work zone present and also during normal operating conditions. In traditional LCCA, adopted by many agencies around the United States, it is assumed that the difference in user cost between alternatives mainly arise from work zone costs. The costs that arise during normal operating conditions (mainly vehicle operating costs) are not dependent on project alternatives and thus are traditionally considered to be negligible. This paper introduces a methodology to test the sensitivity of vehicle operating costs to roughness and texture profile quantitatively and evaluate its contribution to LCCA calculations. It was hypothesized that even the slight changes in surface profile between various alternatives may result in different user costs between the alternatives. A case study is presented to illustrate the effect of user costs of normal operating conditions on LCCA analysis results. Case study showed that vehicle operating costs that arise during normal operation may greatly affect the results of LCCA and should be considered, especially for low-volume traffic projects.