Abstract: A method, system, and computer program product for shipping route selection and transportation planning systems. The computer-implemented method commences upon receiving a set of candidate transportation carrier descriptions, individual ones of the set of candidate transportation carrier descriptions having one or more shipping mode options and having one or more shipping unit options. Then, the method evaluates combinations of using multiple transportation carriers that provide any of the one or more shipping mode options with compatible shipping unit options to determine a combination cost for each of the combinations. Based on the combination costs, the method selects an equipment option that corresponds to the lowest combination cost. Low-cost itineraries can be formed by calculating the cost of a particular itinerary by summing combination costs of constituent legs.