Research

Key resources and continuing-education credit from a recent MXD workshop at Arlington County’s Mobility Lab

Jurisdictions around the country are looking at how they measure and attempt to predict the transportation effects of new development.

Some places, such as California, are moving away from using vehicular level of service (with an “A” grade being no traffic and “F” being a standstill) as an indicator of impacts, and instead looking at vehicle miles traveled and other effects that are directly related to the costs of maintaining services and infrastructure or the environmental impacts of mode choices.

When it comes to approving new development projects, vehicle use (in the form of, say, trips or parking demand) has long been a key feature of community discussion. Historically, the available models haven’t done a great job at capturing the movement of people, since they’ve been focused on car movement. In urban places, though, people walking, biking, or taking public transportation are typically a very large share of all trips being made, and they all need to be considered in terms of provision of infrastructure and services.

This fixture on car impacts is therefore starting to change.

On December 5, 2017, Arlington County, Virginia, held a 3-hour workshop (at Mobility Lab, located in Rosslyn area of Arlington) to coincide with a process that the county’s staff is undertaking to update Arlington’s Traffic Impact Analysis (TIA) requirements for new special exception development projects.

You can hear the entire presentation and see the slide shows here:

Arlington’s “Multimodal Transportation Assessment” (MMTA) update process currently underway seeks to bring the requirements for development proposal submittals up to spend with the county’s needs for information on how trips of all mode types are being generated by new development.

While this update process is supported by transportation consultants Kimley-Horn, the workshop was led by Fehr & Peers DC, and is focused on the evolution of trip generation modeling from the Institute of Transportation Engineers to the U.S. EPA’s Mixed-Use Trip Generation Model to Fehr & Peers MXD+ to tailored jurisdiction-specific modeling such as TripsDC.

Fehr & Peers are national experts on this topic, and were key to the development of EPA MXD a decade ago. Participants and questions and answers came from Arlington County staff, The District Department of Transportation, the City of Alexandria, the Virginia Department of Transportation, several local transportation consulting firms, and a representative from Arlington’s Transportation Commission.

To help guide you in watching the video above, the workshop covered the following content:

1. The relationship between ITE and MXD models for vehicle and person trip generation
2. How consultants for developers would use EPA MXD to prepare trip-generation projections for a new project, including a detailed demonstration of the EPA MXD tool
3. The ways that assumptions are selected and tailored to run the MXD model for a given project and given jurisdiction
4. A comparison of five recent Arlington development project trip-generation observations with EPA MXD and MXD+ predicted results for the same project
5. The differences, features, strengths, and limitations of the tool recently customized for DDOT in its TRIPS DC model, and
6. Additional tools, such as TDM models, that are related to transportation impact analysis and which can be used with EPA MXD as a base.

Key takeaways

Well, I don’t want to give it away if you are listening in! Suffice it to say, the available models are improving every year, but there continues to be room for improvement and there is no substitute for good local data whether you have the means to develop a predictive model around those data or not.

The choice of what approach to take when evaluating development proposals in your jurisdiction really depends on what tools you have available, expectations that may exist at the state level or associated with funding streams, the nature of community involvement in development decision making, and the role of plans and policies in paving the way for certain types of development, and certain types of trip-making behavior.

Here are brief bios for the speakers, and tips if you want to listen to this webinar for continuing education credit.

Speakers

Alex Rixey, Fehr & Peers DC

Alex has diverse, multimodal transportation and land-use project experience at a variety of geographic scales, ranging from single development sites to regional long-range plans. Alex has led projects serving public- and private-sector clients, including travel demand modeling; transportation and parking studies; master plan, transit neighborhood plan, and mobility element development; and data analysis and visualization, with an emphasis on analyzing the effects of built environment and demographic characteristics on demand for all modes of travel. Alex is proficient in the use of SAS, SPSS, and ArcGIS software, and has combined his passions for quantitative analysis and bicycling by developing a station-level bikesharing ridership model. In the transit space, he combined General Transit Feed Specification (GTFS) data with cellphone-based big data to pilot an innovative transit market-analysis methodology. Alex has also recently worked to develop multimodal transportation performance measures that incorporate land use, transportation, and accessibility factors for auto, transit, bicycle, and pedestrian modes as alternatives to the traditional Level of Service metric.

Anjuli Bakhru, Fehr & Peers DC

Anjuli is an emerging transportation engineer with five years of experience in transportation planning and traffic engineering. She provides a diverse background in traffic operations and simulation, including technical expertise in applications such as SYNCHRO, HCS and VISSIM. She has served as technical lead or project manager for numerous high-profile transportation projects that have included traffic engineering, regional bicycle-facilities planning and design, transportation demand management, parking analysis, area-specific planning, and traffic calming.

Continuing Education Credit

This workshop has applied for continuing-education credit for the American Institute of Certified Planners (AICP). For people viewing the recording in the future and requesting OnDemand credits, this blog post offers a venue for online discussion and comment, and you can use the comments section below to offer responses to follow-up questions demonstrating your acquisition of knowledge:

1. What are some of the strengths and weaknesses of ITE’s trip generation model? EPA MXD? Trips DC?
2. What are the key factors or variables that have the greatest influence on outputs in MXD?
3. What was the result of the comparison between MXD’s and Arlington County’s direct observation at five development sites?
4. What is the major, structural difference between MXD and Trips DC?
5. Based on this presentation, what are some strategic considerations jurisdictions might use for incorporating trip generation into development impact assessment?

To log your credit, do an APA CM Search for event ID #9139982, or search with the term “MXD.”

Thanks for listening!