Background - Ongoing Projects - Completed Projects - Reports - Movies - Presentations - Media - Contacts

Background

The I-35W bridge over the Mississippi River in Minneapolis collapsed on August 1st, 2007. This tragedy has led to significant losses. For planners and traffic engineers, this event also brought a great challenge in traffic management and sequential mitigation approaches. An understanding of its impacts on travel behavior is the first, and arguably the most important step to maintain and improve good functioning of our traffic network. To see some evidence of change in travel behavior, and for additional information please refer to the following:

The Transportationist: I-35W bridge collapse - What happened on August 1st and after

Description from Wikipedia

Reaction from Minnesota Department of Transportation

Ongoing Projects

Traffic Flow and Road User Impacts of the Collapse of the I-35W Bridge over the Mississippi River Minnesota Department of Transportation
Cost: $200,502. Time: Two years (June 1, 2008 - May 31, 2010)

Additional Support: University of Minnesota Metropolitan Consortium ($30,000)

David Levinson (PI), Henry Liu (co-PI), Kathleen Harder (co-PI)

with Vehicle Monitoring Technologies (Randall Guensler, Jennifer Ogle)

The collapse of the I-35W bridge over the Mississippi River and its subsequent reconstruction provide a unique opportunity to observe the response of transportation systems to major disruptions that affect their operation. This research project proposes to evaluate the effect of the bridge closure on observed travel behavior, shifts in traffic flows, and resulting effects on alternate routes. In order to conduct this evaluation, a critical first step is collecting timely and complete primary data on travel choices and traffic flows. We propose to use a combination of paper and computer-based surveys to collect data on travel behavior of those affected by the bridge closure before and after the reconstruction of the bridge, in addition to real-time route choice and location data from global positioning system (GPS) units. These data sets will be used to summarize and model travel behavior changes prior to and following the reconstruction of the bridge, and to predict the distribution of traffic flows and impacts on alternate routes. Observed and modeled traffic flows will be used to provide estimates of road user costs associated with the bridge collapse.

BRIDGE: Behavioral Response to the I-35W Disruption: Gauging Equilibration National Science Foundation
Cost: $300,000. Time: Two years (October 1, 2008 - September 30, 2010)

Henry Liu (PI), David Levinson (co-PI), Kathleen Harder (co-PI), Nikolas Geroliminas (investigator)

The recent collapse of the Interstate 35W Highway Bridge over the Mississippi River in Minneapolis has resulted in immediate loss of life and serious consequences for mobility and accessibility in the Twin Cities metropolitan region. The bridge collapse was a terrible human tragedy, but it also brings researchers a rare opportunity to conduct travel behavior and transportation network modeling research that otherwise could not be conducted. It provides us with a unique natural experiment to study two related processes as they are affected by network disruption, namely, travelers’ day-to-day learning and adaptation and traffic equilibration. Most researchers have assumed transportation demand and supply are operated in a steady state of equilibrium. The equilibration process leading to the equilibrium state is largely overlooked, however, mainly due to the limited data available under such situations. Given the network disruption of the I-35W bridge collapse, travelers have been forced to learn new traffic patterns and eventually (over a period of weeks or months), network traffic may (or may not) evolve into a new equilibrium. To date, very few studies have examined the day-to-day behavioral response of travelers after a severe and unplanned network disruption. In addition, no empirical evidence can be found to support current theories regarding traffic equilibration. This project aims to fill that gap. The proposed research is built upon a recent funded NSF Small Grant for Exploratory Research (SGER) project that aims to collect perishable travel behavior and traffic data after the bridge collapse. Using continuous and comprehensivedata collection from other related studies, the goal of this project is to develop and establish a firm foundation for travel behavior models that can answer the following three open questions: 1) How do travelers respond in terms of their trip-making in a day-to-day context under network disruption? 2) How do traffic patterns evolve from a disequilibrium state toward an equilibrium state? 3) How should transportation agencies prioritize the allocation of transportation resources in response to the network disruption, particularly during the process of traffic equilibration? Answering these questions will make a major leap forward in transportation science.

Completed Projects

Small Grant for Exploratory Research: Responding to the Unexpected: Understanding Travelers' Behavioral Choices in the Wake of the Mississippi River Bridge Collapse. National Science Foundation
Cost: $17,000. Time: One year.

Henry Liu (PI), David Levinson (co-PI), Kathleen Harder (co-PI)

This research aims to (1) Collect both aggregated traffic data and disaggregated panel survey data that will help to understand the traveler’s behavioral choice and traffic pattern evolution after the event; (2)Perform preliminary analysis on collected traffic data; and (3) Identify short-term and long-term research needs concerning traveler’s behavioral response and traffic management strategies after network disruption.

Reports

Zhu, S, D. Levinson, H. Liu, and K. Harder (2008) The traffic and behavioral effects of the I-35W Mississippi River bridge collapse (under review)

Xie, F. and D. Levinson (2008) Evaluating the Effects of I-35W Bridge Collapse on Road-Users in the Twin Cities Metropolitan Region (under review)

He, Xiaozheng, Saif Jabari, and Henry X. Liu (2008) Modeling Day-to-day Trip Choice Evolution under Network Disruption (under review)

Tilahun, Nebiyou and David Levinson (2008) I-35w Bridge Collapse: Travel Impacts and Adjustment Strategies(working paper).

Movies

I-35W Bridge Collapse: Difference in Daily Traffic Counts after - before 20 MB

I-35W Bridge Collapse: 15 Minute Traffic Patterns on August 1 (August 1 - July 25) 20 MB

SGER Project (completed)

Letter to survey participants

Dear participants:

We ask your help to participate in a survey on the travel behavior impacts of I-35W Bridge collapse. The purpose of this survey is to advance our understanding of travel behavior changes in the wake of major transportation network disruption. Your responses will help us understand how travelers adapt to network changes, determine on what criteria those decisions are made, and reveal what information resources assist in making those decisions. Answers to these questions could help planners and traffic engineers in both traffic management and planning after major incidents and over the long term.

The survey is conducted by the Department of Civil Engineering of the University of Minnesota and participation in this study is voluntary. All information collected will only be used at a statistical level and for research purposes. Please complete the questionnaire and draw travel routes on the maps, following the instructions provided. Then put both of them in the prepaid envelope and drop them in the mailbox. If you have any question, please contact the principal investigator of this project, Prof. Henry Liu, at 612-625-6347. Thank you again for your participation.

Survey Forms

Click here to see

Presentations

Media

StarTribune Coverage

Adaptable drivers avert expected gridlock by Jim Foti and Pam Louwagle (Sept. 10, 2007)

Editorial: Lessons of adversity in bridge collapse: Commuter creativity is worth studying. (Sept. 13, 2007)

MPR Coverage

I-35W bridge collapse could produce U of M traffic headaches by Art Hughes, Minnesota Public Radio (August 30, 2007)

Newsweek Coverage

CAMPAIGN 2008: Bridge to the GOP: Will the Twin Cities be ready for the Republican convention? by Hilary Shenfeld (Jun 17, 2008)

Contacts

Contact Information:

David Levinson or Henry Liu

Department of Civil Engineering

University of Minnesota

500 Pillsbury Drive S.E.

Minneapolis, MN 55455