Modeling the commute mode share of transit using continuous accessibility to jobs

Recently published

Owen, Andrew and  David M. Levinson (2014) Modeling the commute mode share of transit using continuous accessibility to jobs Transportation Research Part A: Policy and Practice Volume 74, April 2015, Pages 110–122

Fig. 5.  Transit accessibility coefficient of variation over 7–9 AM period.
Fig. 5.
Transit accessibility coefficient of variation over 7–9 AM period.


  • Accessibility to jobs by transit is calculated for departures at each minute.•
  • Detailed spatial resolution more accurately reflects walking trip components.
  • Higher transit mode share is associated with higher average transit accessibility.
  • Higher transit mode share is associated with lower variation in transit accessibility.

This paper presents the results of an accessibility-based model of aggregate commute mode share, focusing on the share of transit relative to auto. It demonstrates the use of continuous accessibility – calculated continuously in time, rather than at a single of a few departure times – for the evaluation of transit systems. These accessibility calculations are accomplished using only publicly-available data sources. A binomial logic model is estimated which predicts the likelihood that a commuter will choose transit rather than auto for a commute trip based on aggregate characteristics of the surrounding area. Variables in this model include demographic factors as well as detailed accessibility calculations for both transit and auto. The mode achieves a ρ2 value of 0.597, and analysis of the results suggests that continuous accessibility of transit systems may be a valuable tool for use in modeling and forecasting.

Elsevier is offering a FREE DOWNLOAD Until April 26, 2015.

TCRG: Observing Accessibility

I will be presenting at the Twin Cities Research Group at 12 Noon at the Wilder Foundation building at University and Lexington on Wednesday March 11
Title: Observing Accessibility
Abstract: Using data from the Access to Destinations Studies and the Access Across America Studies, this talk discusses both the measurement of accessibility, why it matters, and how it might affect traveler behavior, institutional behavior, and public policy. Looking at data from rail development in London in the 1800s, the Twin Cities from 1995 to the present, and 51 metropolitan areas across the US, implications about the effects of accessibility are described, and the rationale for a National Accessibility Evaluation is presented.
(This is a sequel to my August 2009 talk: Destinations Count)

Better job accessibility drives MnPASS subscriptions

CTS Catalyst reports on our recent research: Better job accessibility drives MnPASS subscriptions


Photo: MnDOT

In recent years, many metropolitan-area highway systems have created high-occupancy toll (HOT) lanes. Typically, the use of these lanes is restricted during peak periods to carpools and those paying a toll for access, which commonly requires enrollment in an electronic tolling program and the use of an electronic transponder.

To better understand why drivers enroll in Minnesota’s MnPASS electronic tolling system, University of Minnesota researchers investigated the factors that drive subscriptions. Their findings indicate that households are more likely to have MnPASS subscriptions in areas where the MnPASS system provides a greater increase in accessibility to jobs.

“While there has been a great deal of research into what causes travelers to select a toll lane during a single trip, there is very little information available regarding the first decision a potential HOT lane user must make—the decision to enroll in an electronic tolling program and become an eligible HOT lane user,” says Andrew Owen, director of the U’s Accessibility Observatory.

The MnPASS system was created in 2005 with the opening of HOT lanes on I-394 west of downtown Minneapolis; in 2009, the system was expanded to include HOT lanes on I-35W south of downtown Minneapolis. During peak periods, the lanes are restricted to vehicles carrying two or more occupants and to travelers paying a toll that varies from $0.25 to $8.00 based on HOT lane utilization at the time. To use the HOT lanes, vehicles must enroll in the program online, by mail, or in person and pay $1.50 a month to carry a MnPASS transponder provided by the Minnesota Department of Transportation (MnDOT).

“Though enrolling in a HOT lane program is usually low-cost or free, it always requires some user expense in the form of time spent processing enrollment forms and managing accounts,” says Owen. “In addition, it involves some risk because there is typically a charge for lost or damaged transponders. Because of these costs and risks, it’s reasonable to expect people who would receive little or no benefit from the ability to use HOT lanes won’t enroll in the program, while a person who would receive a very large benefit would be very likely to enroll.”

To test this theory, researchers calculated the job accessibility benefit of the MnPASS system by determining the areas where using MnPASS HOT lanes would lead to the greatest increase of jobs reachable with a commute of 30 minutes or less. They found that the areas with the highest concentrations of MnPASS-holding households—the western and southern suburbs of the metro area—were also the areas where the MnPASS system provided the greatest accessibility benefit.

“These findings will serve as a useful tool for transportation planners as they work to determine where to implement HOT lanes in the future,” says Owen. “By evaluating the incremental job accessibility benefits created by a planned HOT lane, planners can more effectively model participation in toll lane programs and more accurately weigh the costs and benefits of creating new HOT lanes.”

Related Links

Minnesota Compass

Minnesota Compass collects social indicators to measure changes over time in Minnesota across a variety of topics, including transportation, education, economy and workforce.  Of interest to Transportationist readers are transportation indicators. These include congestion, pavement condition, transportation expenses, and accessibility, from the Accessibility Observatory. Check it out if you are interested in performance and trend tracking.

Access Across America: Transit 2014 Data

Access Across America: Transit 2014 Data is now available for download at the University of Minnesota Library Digital Conservancy.

This data was created as part of a study that examined the accessibility to jobs by transit in 46 of the 50 largest (by population) metropolitan areas in the United States. It is the most detailed evaluation to date of access to jobs by transit, and it allows for a direct comparison of the transit accessibility performance of America’s largest metropolitan areas.
Related Publications

Andrew Owen, David M Levinson. Access Across America: Transit 2014. (2014). Center for Transportation Studies Research Report. September 2014. Report no. CTS 14-11.
Suggested Citation

Owen, Andrew; Levinson, David, M.(2014). Access Across America: Transit 2014 Data [dataset]. Retrieved from the Data Repository for the University of Minnesota,

New National Accessibility Evaluation pooled-fund study solicitation is live

Accessibility Observatory banner

New National Accessibility Evaluation pooled-fund study solicitation is live 

This new pooled-fund project, led by the Minnesota Department of Transportation, will implement a measurement of accessibility to jobs across the entire United States. For every Census block, it will calculate the number of jobs that can be reached, by driving or by transit, within various travel time thresholds. Each pooled-fund partner will have direct digital access to these detailed accessibility datasets. In addition, an annual report will summarize the accessibility dataset for metropolitan areas across the country.

Accessibility combines the simpler concept of mobility with an understanding that travel is driven by a desire to reach destinations. Accessibility metrics combine network travel times with the locations and value of the many origins and destinations served by a multimodal transportation system. Accessibility evaluation has applications in a variety of areas, including performance management, scenario evaluation and analysis, transportation and land use research, and transportation equity.

To join the study, view the Transportation Pooled Fund Program solicitation. For more information, visit the pooled-fund study web page.

Accessibility moves out of the lab and into practice

Eric Sundquist at SSTI writes: “Accessibility moves out of the lab and into practice

Accessibility, long considered a more robust measure of transportation system success than simple mobility, is moving out of research and into practice, according to panelists on an SSTI webinar.

Accessibility measures the ease by which travelers can reach desired destinations, or “opportunities.” Often, but not always, it is measured in terms of time. As such, it combines both mobility and proximity of land uses, bringing together two directly connected public policy concerns that are often poorly integrated in decision-making.

While accessibility is not a new concept, data limitations have made it difficult to measure. Now it is becoming practice-ready, panelists said.

The webinar, broadcast Dec. 4, featured Andrew Owen of the University of Minnesota’s Accessibility Observatory, Richard Kuzmyak of Renaissance Planning Group, and Kate Sylvester of the Maryland DOT. Slides and a recording are available on the SSTI website.

Owen, who cited commentary in the conservative National Review and libertarian Reason Foundation about the benefit of accessibility measures, has been working with Minnesota DOT and now is developing a pooled fund study to mainstream accessibility measures across the country. Kuzmyak has applied accessibility measures in the Washington, D.C., area, including in a project with Sylvester’s Maryland DOT.

While both efforts aim to make use of accessibility for better transportation and land use decision-making, the approaches are somewhat different.

Owen’s group uses a cumulative opportunities count, generally using jobs as the critical opportunities. They estimate the number of opportunities that can be accessed by car and transit from neighborhoods around the nation within a set time, say 30 minutes. …