| Intercity passenger transportation is a time and energy intensive activity. Despite a growing social consciousness toward "green" alternatives, travelers continue to choose routes and modes based primarily on their travel time and cost. While long distance trips of greater than 500 miles are dominated by air travel, short- and medium-haul trips compete with surface modes when comparing total travel time and cost. However, due to hub-and-spoke air transport networks, short-haul air travel, between large airports and small airports, is bundled with long-haul itineraries. At hub airports, passengers can experience lengthy transfer times between short and long-haul flights, and these can provide an opportunity for competitive mode substitution. This research develops an evaluation framework to measure and compare short-haul substitutability through an analysis of seventeen short-haul markets transferring though Chicago's O'Hare International Airport. By considering three primary measures: travel time, operator cost and energy consumption, the results suggest that mode substitutability is not directly associated with distance, and that there are competitive opportunities for ground modes that may offer improved service options as well as sustainable advantages. The trade-space model proposed here can be considered a "model of models," modular in design combining a variety of literature-based models, estimation techniques and estimated cost functions. The purpose is to design flexibility into the model to test better alternatives as they are available. |
