• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.7-16
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• 2011

This study investigates the degree of dependency on freeways when auto travelers make route choices in the Seoul Metropolitan Area. The investigation is conducted based on aggregated auto trip data, defining the degree of dependency as the proportion of auto trips selecting freeways in their travel paths. The analyses reveal that the trips departing from the areas with higher accessibility to freeways tend to exhibit higher dependency on freeways. In addition, the dependency is significantly affected by the travel time differences between two paths including and excluding freeways, respectively. The number of service interchanges was found to be one of significant factors for trips to Incheon and Gyenggi areas. The finding indicates that the factors affecting the degree of dependency on freeways may vary depending on the areas' characteristics. The findings would enhance the understanding of drivers' route choice behavior in Seoul at an aggregate level.