In this paper, an algorithm framework is developed to find energy-optimal routes for a mixed fleet of delivery vehicles. The fleet could be composed of Battery Electric Vehicles (BEVs), Hybrid Electric Vehicles (HEVs), and Internal Combustion Engine-powered conventional Vehicles (ICEVs) operating over the same service area from a common depot. Additionally, in the case of an HEV, the onboard energy management optimization determines the power split between the power sources on the vehicle based on the route information available. The framework presented in this paper takes into account information related to static conditions (such as topography, payload, and driving distance) and dynamic driving conditions (such as traffic incidents and traffic lights). The route optimization can then be done for various cost functions such as energy consumption, operating costs or maximizing goods throughput. The simulation results demonstrate elements of the route planning framework for benchmark grid problems and real-world road maps.