Researchers at the TIDE Center have developed an algorithm that finds the best path when path costs are nonlinear and hence, nonadditive. The nonadditive path calculator uses an iterative process that produces a handful of candidates for the optimal path and, upon termination of the algorithm, evaluates the total cost in terms of value of time and tolls to determine the overall best path. It's an efficient means of solving a hard problem.
You can use the on-line Path Calculator to explore these ideas for yourself.
Instructions: