Trade-offs Between Initial and Maintenance Costs of Highways in Cross-Slopes

Abstract

Highway maintainability is a significant issue, which should be considered in the planning stages of a highway development process. A number of infrastructure models such as highway maintenance management systems, bridge management systems, and pavement management systems have been developed to predict future maintenance expenditures. However, these models only predict maintenance costs after a highway is built, and do not provide the flexibility of exploring various alternatives in the planning stages. In this work formulations for initial and maintenance costs have been developed based on the design variables which can be chosen to minimize these costs, focusing on the sideslopes in cut and fill sections. Maintenance cost has been represented as a function of sideslope width of highway cross section and annual average daily traffic. Sideslope is represented as a function of soil type. The proposed formulations are used in a highway design optimization model to optimize highway alignments. An example is presented to investigate the sensitivities of maintenance cost and soil characteristics in selecting alignments, using a real geographic database from Maryland. The results indicate that maintenance cost and soil characteristics are important considerations in alignment optimization.