MODAL SPLIT. DOCUMENTATION OF NINE METHODS FOR ESTIMATING TRANSIT USAGE

The report documents nine procedures that have been developed between 1955 and 1966 by nine urban area transportation studies to estimate the proportion of future intracity travel demand for the two alternate modes of transportation; i.e., public mass transit and the private automobile. These procedures are called modal split models. Of the nine models, five are classified as trip-end models and four are classified as trip-interchange models. A trip-end model is one that allocates a portion of total person trip origins and destinations to alternate modes of transportation prior to trip distribution. A trip-interchange model is one that allocates portions of given person trip movements resulting from trip distribution to the alternate transportation modes. Factors found significant in determining modal split have been grouped into three categories: (1) characteristics of the trip, (2) characteristics of the transportation system.