A multiple-objective model based on the network optimization system

The objective of the current network optimization system (NOS) model used in Arizona is to minimize annual pavement preservation cost over the planning period. This paper uses an alternative NOS model with the objective of maximizing pavement performance with the consideration of minimizing annual cost. Instead of solving a single objective function, the paper presents a model to solve two objective functions of simultaneously maximizing pavement performance and minimizing annual cost through the use of a program called MNOS. Based on the computed results, the decision-maker can obtain desired pavement performance in an expected annual cost level. This model uses a three-step method to divide the two-objective problem into three single-objective problems. By solving each of them using a Fortran solver DLPRS, the desired performance is achieved in a minimal budget scenario. Based on their practical experience and expectations, decision-makers can analyze a set of solutions, choose the desired budget levels, and obtain expected pavement performance levels, which are always kept at or above the required values.