The General Aviation Airport Choice model is an attempt to model General Aviation (GA) travel patterns in the US in order to provide a means of assessing the impact of General Aviation activities on the National Air Space system. The model will also serve as part of transportation planning tool to help assess the viability of deploying NASA's Small Aircraft Transportation Systems (SATS) aircraft as a competitive mode of transportation for intercity travel. The General Aviation Airport Choice model developed estimates General Aviation (GA) person-trips and number of aircraft operations given trip demand in the form of GA person trips from counties. A pseudo-gravity model is embedded in the model to distribute the inter-county person-trips to a prescribed set of airports in the US. The airport-to-airport person-trips are split into person-trips by three aircraft modes (single, multi and jet engine) using an attractiveness factor based on average occupancy, utilization and a distance distribution factor for each aircraft type and the number of aircraft based at each airport. The person-trips by aircraft type are then converted to aircraft operations using occupancy factors for each aircraft type. The final output from the model are aircraft operations trip-tables by aircraft type between the airports in the model. The GA trips are estimated in order to provide a means of assessing the impact of GA activities on the National Airspace System. The model output may be used to assess the viability of GA aircraft serving as a competitive mode of transportation for intercity travel. / Master of Science

The aim of this study was to develop a framework to model travel choice behavior in order to estimate intercity travel demand at nation-level in the United States. Nested and mixed logit models were developed to study national-level intercity transportation in the United States. A separate General Aviation airport choice model to estimates General Aviation person-trips and number of aircraft operations though more than 3000 airports was also developed. The combination of the General Aviation model and the logit models gives the capability to estimate a full spectrum of intercity travel demand in the United States. The logit models were calibrated using a nationwide revealed preference survey (1995 American Travel Survey). Separate models were developed for business and non-business trip purposes. An airport choice model is integrated into the mode choice model to estimate both the market share between any origin-destination pair and other modes of transportation, and the market share split between airports associated with the origin-destination pairs. The explanatory variables used in the utility functions of the models are travel time, travel cost, and traveler's household income. The logit models are used to estimate the market share of automobile and commercial air transportation between 3091 counties and 443 commercial service airports in the United States. The model was also used to estimate market share for on-demand air taxi services. Given an input county-to-county trip demand table, the models were used to estimate county-to-county travel demand by automobile and commercial airline between all counties and commercial service airports in the United States. The model has been integrated into a computer software framework called the Transportation Systems Analysis Model (TSAM) that estimates nationwide intercity travel demand in the United States. / Ph. D.

A weakness with the Swedish Transport Administration’s model for long-distance trips is that it onlyallows for one mode of transportation per trip. A long-distance trip usually consists of several modesof transportation, while the current model does not allow modelling of, for example, a flight with aconnecting car, bus or train transfer. This is problematic as a significant part of the generalized costof travel can be derived from an access trip.The master thesis has been devoted to studying how a model for choice of access mode anddeparture airport can be designed. The work has been limited to study long-distance trips starting inStockholm county, carried out by residents of the county. The airport choice has been limited toArlanda and Bromma Airport.In a literature review, the underlying mathematical theories which the project is based on arepresented. The theory originates from the work on discrete choice models by Daniel McFadden,which later was further developed and summarized by Kenneth Train. By studying previous researchdealing with modelling of access mode and airport choice, it can be concluded that there is noobvious approach to model design, apart from the fact that the model should be based on the logittheory.The observations on which the model is estimated are retrieved from travel surveys conductedduring 2011-2016. A cost estimate for the modes of travel included in the model has been donemanually. Travel times for all modes have been generated using the Swedish TransportAdministration’s regional base model for Stockholm County dated 2014, using the macro simulationsoftware Emme.Out of all the estimated models, one model is presented as the best and final one. It is a multinomiallogit model divided into two segments, one for business travelers and one for private travelers. Themodel is analyzed by calculating value of time, cost- and time elasticity for each of the alternatives inthe choice set. For some of the alternatives, the value of time is relatively high, which is addressed inthe concluding discussion.