The OKI model includes two MPOs, the Miami Valley Regional Planning Commission (MVRPC) and OKI, spanning eleven counties: seven in Ohio, three in Kentucky, and one in Indiana. The program runs on Cube Voyager and custom programs, most of which are run through FORTRAN. Figure 1: OKI Modeling Areaprovides an illustration of the modeling area. Table 1: OKI Model Statistics provides a basic model statistical summary.
The OKI model was created in 1968 and first applied in 1971. The following list provides a timeline of the OKI model's development and enhancement. It also includes various factors that have influenced the model building environment:
The model is applied to a variety of study types, such as bridge and toll diversion analysis; rail and streetcar corridor analysis; long range transportation planning, specifically 2004 and 2008 regional plans; express and local bus planning for four different transit operators, Metro, Tank, Clermont, and Dayton; and attainment estimation for ozone and fine particulates.
OKI was the first MPO to implement the Motor Vehicle Emission Simulator (MOVES) and has also collaborated with FHWA to apply the Surface Transportation Efficiency Analysis Model (STEAM) for economic analysis of large transportation projects.
In the existing structure, OKI runs a modified trip-based model. This model performs a household classification process that provides input to trip generation estimation by wealth classes based on the number of workers per household compared to the number of vehicles (for home-based work trips) or the number of people in the household compared to the number of vehicles (for home-based other trips). The distribution is an un-stratified gravity model. Mode choice is a nested-logit process that is based on wealth classes. Assignment is a bi-conjugate equilibrium assignment. The model performs a feedback procedure for trip distribution and mode choice by time of day.
Prior to the OKI peer review, the OKI model applied 1995 household and transit surveys and validated to 2005 traffic counts and transit ridership. By the time of the peer review in spring 2014, OKI calibrated the model using 2010 household and transit on-board surveys combined with data from the 2010 decennial census and 2005-2010 American Community Survey (ACS). In the last five years, OKI also has collected a massive number of traffic counts and has enhanced the highway network file to include more variables. Additionally, OKI has improved model output reports and streamlined the model process.
OKI is currently working with the Ohio Department of Transportation (ODOT) to develop an activity-based model, using the Coordinated Travel - Regional Activity-Based Modeling Platform (CT-RAMP).This development is expected to take at least until June of 2015.
As referenced in Section 3.1, OKI has conducted three other peer reviews in the past. The first peer review was in 1996 to assess the then-current TDFM in view of the regulations and policies established by the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA). Two years later in 1998, the panel was reconvened to review progress and provide suggestions for model use in then-active transportation studies. The third peer review panel was convened in 2003 to comment on several factors surrounding the model's adequacy and consistency with the state of the practice. Several recommendations from the 2003 peer review have been completed or have been investigated prior to this peer review. Table 2 summarizes the status of those items.
OKI identified three reasons for the peer review in their application. First was to reaffirm that the current trip-based model structure, procedures, and results meet the needs of the agency. In areas where the need is not met, OKI requested the suggestion of short term improvements. Second, OKI requested that the panelists identify any improvements that can be quickly implemented utilizing data or data that can be easily collected. Finally, the OKI staff sought guidance on their effort to transition to a tour-based model. The tour-based model is targeted for summer of 2015, but it is expected that both the trip-based and tour-based models will run parallel for a couple of years. OKI emphasized the importance of ensuring that the trip-based model meet the needs of regional transportation planning activities and the key projects until the transition is complete.
At the time of the peer review, OKI identified the following additional areas of priority for the panel to address:
