The purpose of this dissertation is to examine different underexplored complex transportation problems. First, vehicle routing problem (VRP) with stochastic travel times is examined. The major goal is to consider and model the impact of the correlation on the makespan-minimizing objective function. Further, a two-tier delivery network with robots operating on the second tier is considered. Compared to conventional truck-based deliveries, robot-based deliveries can save up to 90%, for a scenario with customer time windows.