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Application of a Microsimulation Model for User Benefit Calculation in Transit Projects Peter Vovsha, PB Consult, Parsons Brinckerhoff Inc. F TA has requirements for a travel demand model that create a certain bias in the comparison between regions is used to estimate user benefits (UBs) of transit proj- because some metropolitan planning organizations have ects. These requirements are based on the general already developed activity-based models, while the methodology of UBs as the difference between total com- majority are still using conventional four-step models. posite utilities calculated before and after project intro- Under these circumstances and primarily for practical duction. The current FTA approach limits the cor- purposes, a constructive way is proposed to adjust the responding scope of choices over which the composite util- activity-based model output to the requirements of the ity is calculated to mode and route choices. Thus, the total conventional UB calculation procedure. trip table is assumed fixed, and the mode and route choice The general structure of the MORPC model system attributes that are necessary for calculation of the compos- and the most important and relevant components are ite mode choice utility are reported. The FTA approach shown in Figure 1. A set of day-level models that corre- and developed software SUMMIT have been primarily sponds to coordinated daily activity patterns for all designed for four-step models characterized by an easy dis- household members appears as a single upper-level stage integration of the trip-distribution and mode-choice stages with no details because this paper is devoted to mode as well as the aggregate zone-to-zone structure of the model choice issues. output. The new generation of activity- and tour-based The subset of tour-level models includes the following microsimulation models, of which the Mid-Ohio Regional components: Planning Commission (MORPC) model is one representa- tive, requires a certain reconsideration of the UB calcula- Primary tour destination model that defines which tions in view of the more complicated structure in which of 1,805 zones and which of three subzones (with no trip distribution and mode choice stages are closely access to transit, long walk to transit of 0.5 to 3.0 mi, or intertwined--as well as because of the fully disaggregate short walk to transit less than 0.5 mi) are chosen for each (individual-record) structure of the output. tour; In theoretical terms, the behaviorally realistic and Time-of-day model that defines departure-from- detailed output of the new models offers numerous addi- home and arrival-back-home combinations of hours tional possibilities for quantifying UBs of transit projects from 5:00 a.m. (or earlier) to 23:00 p.m. (or later). compared with the composite mode choice utility. How- Departure-from-home hour is associated with the out- ever, taking advantage of the activity-based approach for bound half-tour timing, and arrival-back-home hour is the UB calculation is a long-term issue for which numer- associated with the inbound half-tour timing; ous methodological and technical details should still be Entire-tour modebest transit submode model that developed. Furthermore, extending the UB methodology defines which one of six principal entire-tour modes is for activity-based models (though highly desirable) may chosen for each tour (1, single-occupancy vehicle; 2, 33