Travel Demand Model - OKI

OKI/MVRPC Travel Demand Model – Version 6.01. BackgroundThis is Part VI of the OKI/MVRPC model development report. It has been previously released asthe Task A.4.6, Trip Assignment and Validation, a report that is part of a series of working papersthat document the development of a consolidated travel demand model for the Ohio-Kentucky-Indiana Council of Governments and the Miami Valley Regional Transportation Commission (OKIand MVRPC respectively). This model development is undertaken under the framework of theNorth-South Transportation Initiative, a Major Investment Study focusing on the Interstate 75corridor.This report covers the last two model development activities: trip assignment and modelvalidation. In trip assignment, highway trips are loaded onto the highway network and transittrips are loaded onto the transit network. The consolidated model uses trip assignmentmethodologies similar to those developed for OKI Model v54: highway equilibrium assignmentand all-or-nothing transit assignment. One important enhancement over Model v54 is theimplementation of a multi-class assignment that considers five different modes: singleoccupancyvehicles, two-occupant vehicles, three-occupant vehicles, single-unit trucks andmultiple-unit trucks. This assignment methodology allows testing the effect of transportationsystem and demand management policies such as high-occupancy lanes and truck trafficprohibitions on local and regional traffic movements.Model validation refers to the comparison of estimated and observed individual highway linkloadings and transit route boardings. The purpose of model validation is to gauge howaccurately the model predicts observed base year travel patterns, and to identify potential modelshortcomings and likely improvements. The OKI/MVRPC consolidated model was validatedagainst traffic counts collected between 1994 and 2000, and 1995 transit boardings. As a resultof the validation process, a number of adjustments were made to model parameters in all modelcomponents (generation, distribution and mode choice). This report presents the results of thefinal model validation, with some discussion of the required model adjustments. Additionaldiscussion of these adjustments is available in Parts III to V of the Model Development Report.This report consists of four main parts: Section 2 describes time of day factoring and vehicleoccupancy factoring, operations which take place in preparation for highway assignment;Sections 3 and 4 deal with the highway assignment methodology and validation, respectively,while Section 5 addresses jointly the transit assignment method and validation.Assignment and Validation - Background 1