Office of Planning, Environment, & Realty (HEP)
In preparation for the peer exchange, a short questionnaire was sent to all participants to collect information on their modeling experiences and challenges. The questionnaire was used to refine the meeting agenda, and to develop an understanding of the current modeling situation at the various participating MPOs. The following provides summary information on MPO activities and model usage based on the questionnaire and supplemented with discussions at the peer exchange meeting.
All participants were involved in some form of travel demand modeling, with approximately one third of them using microsimulation. Several had included additional modes (such as transit), and others were very interested in doing so in the near future. All the MPOs are interested in land use and air quality models. A number of specific software packages were mentioned in the survey:
While most MPOs run their own models, many were initially developed by or in coordination with consultants or State DOTs. Several MPOs use models that are run at least in part by consultants or DOTs.
The participants were generally satisfied with their modeling efforts, but recognized a need for improvement, particularly in the areas of data and of dealing with modes other than automobile. One participant (Stephen Williams, Charlottesville, VA) remarked, "We are very happy with the vehicle and transit modes in the model. Bicycle and pedestrian modes are a huge issue in our region and I would like to start modeling those modes." Other participants mentioned the need for more data in order to better model peak periods. Having a high proportion of external trips is sometimes an issue. Frequently mentioned data issues include outdated data and lack of locality-specific data. When the population of an area is small, it can sometimes be difficult to obtain a statistically significant sample. There are also some political and bureaucratic barriers to collecting or otherwise acquiring needed data. Data needs are discussed in more detail later in this report.
The three primary uses of models are:
Participants noted that model use is required for dealing with air quality conformity in non-attainment areas and/or Federal Transit Administration's New Starts applications. There is an interest in using models for operational issues, including ramp metering, signal coordination, and transit priority. In the smaller MPOs the need for modeling is often sporadic. "Modeling requests are few. One example is what happens to traffic volumes if you build a new bridge between two existing bridges five miles apart." (Joe Delmagori, Farmington, NM)
The participating small MPOs are often housed in a larger organization that provides basic office functions. The organization might be a city in the region, or the county planning department, or a regional planning or development council.
They do have active policy committees and most also have technical committees, with representation from the local jurisdictions in the region as well as the State DOT. The committees may sometimes include other important stakeholders, such as an airport authority, major landowners, or a major university.
Models are most often built by the State DOT or by consultants, but in four cases were built by MPO staff. The models are more often run by MPO staff, but sometimes by the State DOT or consultants.
The Champaign County Regional Planning Commission (Illinois) recently completed a research project entitled Travel Demand Modeling Status and Needs Study for the Small and Medium Sized MPOs in Illinois1. The document provides an overview of the status of travel demand modeling, and the need for such models, in Illinois and offers several recommendations for improvements. A key finding of this report, which was discussed in the peer exchange, is the usefulness of a statewide model in providing sufficient contextual information to support modeling and analysis of long-distance or through traffic, which is often a significant element of traffic in small urban areas. Statewide models can also help balance supply and demand over a broader area, which helps a smaller regional model account for effects of projects and development outside of the local model area.
1 The document is available at http://www.ccrpc.org/transportation/pdf/ICT_Final_Report.pdf (accessed 6/22/2012), though readers are advised that it is a 100 megabyte file.