What-if models of pavement management analysis such as RTIM, HERS and HDM-4 predict the consequences of different maintenance options to be tested that are specified exogenously. Therefore, although they are often used to “optimize” maintenance options, they are not optimizing them in its true sense; they are merely used to find the best options among those tested. Since there are usually infinite numbers of options, it is impossible to exhaust all of them and only suboptimal optimizers are found. The present paper proposes the use of gradient search methods with what-if models to find the true optima. It demonstrates through a case study the feasibility of the use of the steepest descent method and the conjugate gradient method along with HDM-4 to find the true optimum maintenance options.
