Travel Demand Model - OKI

OKI/MVRPC Travel Demand Model – Version 6.05. Transit Assignment Methodology and Validation5.1 Transit Assignment MethodologyThe transit assignment consists of two all-or-nothing daily assignments: peak period and offpeak period. Transit trips from the home-based and non-home based purposes are added to theairport and King's Island trips prior to assignment. Transit trips are assigned in PA format, as iscustomary.For the purposes of the validation, student trips were not included in the assignment. Forforecasting purposes these trips will be included in the transit boarding totals.5.2 Transit Assignment ValidationFor the entire region, total transit ridership is estimated within 10% of the observed ridership(see Table 5.1). The estimation error associated with the ridership of each transit agencyincreases as the total observed ridership decreases: boardings for the largest regional agency,SORTA, are estimated with only 2% error, while boardings for TANK, a medium size agency, areestimated with 30% error. City of Hamilton and Middletown exhibit very low ridership; in factthere is some uncertainty about the actual number of observed boardings for these two agencies,and consequently the estimation error shown in Table 5.1 reflects this uncertainty.Tables 5.2 to 5.5 show transit validation statistics disaggregated by corridor, region and route.Given the low observed ridership, it is expected that the estimation errors at these levels ofdisaggregation will be relatively large. Some of this error is due to a mismatch between theroutes represented in the model and the routes for which observed data, either from the onboardsurvey or the independent boarding counts, are available. This issue was referred to in thediscussion about mode choice calibration target values; please see Part V of the ModelDevelopment Report. Overall the transit validation is adequate, particularly given the low sharetransit in regional tripmaking.Table 5-1 Observed vs. Estimated Boardings, by Transit AgencyAgencyObservedEstimated BoardingsBoardings Peak Off-Peak Total% ErrorMETRO 78,099 44,151 32,481 76,632 -2%TANK 9,167 7,588 4,292 11,880 30%City of Hamilton 1000 772 616 1,388 39%Middletown 905 900 616 1,516 68%MVRTA 40883 30,033 16,499 46,532 14%All Transit 130,054 83,444 54,504 137,948 6%Assignment and Validation - Transit Assignment Methodology and Validation 24