Combining discrete-event simulation with an optimization metaheuristic, a method for solving computational problems to obtain a more efficient procedure, provides the basis for a more powerful planning tool for classes of problems where inherent randomness and time domain issues dominate the system. Averitt Express, a leading provider of freight transportation and supply chain management to more than 100 countries, has systems design engineers working on various process improvement initiatives that include optimizing the less-than-truckload network including pickup and delivery, billing, dock, yard and over-the-road operations. The company is currently trying to improve docking operations for freight relays. Clearly, the "best" configuration is dependent on a time-dependent workload of arriving freight. A Visual Basic for Applications function is used to convert trailer arrival times to inter-arrival time between trailers. The search model can use the script to develop a workload for the day that indicates door assignments as well as which trailers are assigned to specific stripping doors.