Ongoing Projects

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

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.

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

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.

Value of Reliability Oregon Transportation Research and Education Consortium
Cost: $330,935. Time: Two years.

The issue of travel time reliability is becoming more critical for the movement of people and freight. In order to examine issues related to the value of travel time reliability, we plan to test drivers’ preferences for alternate commuter routes in a real world setting. The research participants will drive on three different routes in two cities: (1) primarily freeway, (2) primarily arterial roads, and (3) other streets. Freeways have a possible trade-off between high speeds and congestion during rush hour. Arterials typically have a series of traffic signals that may be timed to favor through-traffic. Other routes might have some traffic signals and some stop signs, but they likely have less traffic. By comparing driver perceptions of the alternate commuter routes, it will be possible to determine the weights associated with the different components of travel time. Driver preferences may also be based on qualitative factors such as the attractiveness of the route. Thus one objective of the proposed project is to measure and then model the route preferences of drivers who have experienced real-world alternatives to their regular commute to and from work. Preference data will be obtained after the participants have completed their morning and evening commutes on three alternate routes (customized for each driver). The added realism of the novel data collection method proposed for this project should enable the value of travel time reliability to be used in route preference models. In turn it will be possible to more accurately predict traffic patterns and produce solutions more likely to ameliorate traffic congestion. An additional objective of the proposed research is to make information about local road networks more available to drivers. This will allow for the better use of existing resources and road capacity for normal operations including when drivers are commuting to and from work.

Access to Destinations: Measuring Accessibility by Automobile. MnDOT
Cost: $186,000. Time: Two years.

The goal of the proposed research is to develop accessibility measures for the Twin Cities region during the periods between 1995 and 2005. This will be done in two parts. The first will utilize travel time estimations on arterials and freeways from previous projects as an input to identify the feasible routes (and their travel times) between origin and destination pairs in the region. This will be done through determination of departure time- based route travel times, and will integrate such data with land use information stored in a geographic information system. The second part will include generation of the accessibility measures for the three time periods. Accessibility measures include cumulative opportunity, gravity-based, and place rank measures that were tested in previous research. The final product of this research project will be a comprehensive evaluation of accessibility in the Twin Cities region, which can help in operational planning and in public involvement activities of transportation agencies to ascertain how investments, transportation strategies, market conditions, and land use policies affect the performance of the transportation-land use system.

Value Capture Project State of Minnesota
Cost: $300,000. Time: One Year

The accessibility that transportation networks provide has a direct influence on the value of land, particularly in urban areas. Improvements to transportation networks alter the relative accessibility of places, and thus land values. The capitalization of these accessibility benefits into land value provides a source of benefit that can be extracted in order to finance, at least partially, transportation facilities and services. This practice of “value capture” is particularly useful in cases where it is difficult or impossible to finance improvements from direct user charges. This study will provide an extensive review of the value capture concept. It will review the theoretical and empirical literature on the relationship between transportation and land values, including the measurement of benefits from a transportation improvement. It will also review legal and economic frameworks for capturing the value gains resulting from a transportation improvement. These may include, but need not be limited to, land taxes and other property-based taxes, fees and special assessments, developer contributions and various market-based instruments. The study will conclude with recommendations for each type of value capture instrument. Each will be evaluated on the criteria of efficiency, equity, adequacy and feasibility.

STREET: Simulating Transportation for Realistic Engineering and Education. National Science Foundation
Cost: $500,000. Time: Four years.

Currently, most undergraduate transportation engineering courses are offered in a traditional combination of “chalk and talk” lectures and “paper and pencil” problem-solving exercises, failing to fully motivate students and preventing them from effectively assimilating and applying knowledge in their future work. This approach to education does not expose undergraduate students to the myriad of challenging issues and solution methods that would encourage them to pursue careers in transportation engineering. A new paradigm for transportation engineering education is needed to better engage students and deliver knowledge. Although simulation has been proven to be powerful tool to encourage active learning, the effectiveness of simulation has not been fully examined in transportation education practice, and its potential advantages over traditional ways of learning have not been widely acknowledged. The focus of this proposal is to develop and refine a suite of web-based simulation modules that can be easily incorporated in the undergraduate transportation courses. These simulation modules will be also evaluated in a diverse setting and improved after examining evaluation results. Eventually, the simulation-based teaching materials will become an active textbook, which offers an interactive learning environment to undergraduate students. The active textbook with simulation is expected to improve student understanding of critical concepts in Transportation Engineering and student motivation toward Transportation Engineering and improve student retention in the field. Specifically, targeting the required undergraduate course Introduction to Transportation Engineering, five simulation programs are in the development plan, namely, ROAD: Roadway Online Application for Design, OASIS: Online Application of Signalized Intersection Simulation, SOFT: Simulation of Freeway Traffic, ADAM: Agent-based Demand and Assignment Model, and SONG: Simulator of Network Growth. Prototypes of these simulation programs have been developed (including ROAD, ADAM and SONG) or currently being developed (including OASIS and SOFT) through the PIs’ accumulated works over the last several years. Initial evaluation and testing including the prototypes of ROAD, ADAM and SONG have been conducted in the course offerings at the University of Minnesota - Twin Cities (UMN). The preliminary evaluation results are very positive and encourage us to pursue further. This project will further develop and refine the five simulation modules and integrate them into the undergraduate courses at UMN. Building upon the local implementation success, the simulation modules will be evaluated and tested in the course offerings of over sixteen other transportation programs from different universities across the country. Feedback from the implementation will be provided to the project team for continuing improvement. In addition, to reach an even broader audience with computer simulation, a mobile booth with public-oriented versions of some of the simulation modules will be displayed at the annual Minnesota State Fair and the Minnesota Transportation Museum for public demonstration and education on current transportation problems.

Metropolitan Travel Survey Archive Phase III USDOT Federal Highway Administration
Cost: $25,000. Time: One year.

Economic Impact of Upgrading Roads. Minnesota Department of Transportation
Cost: $72,636. Time: One year.

Improvements to transportation networks, especially those in growing areas, tend to have impacts on local land markets. In principle, an improvement to a link in the network will confer economic benefits to adjacent and nearby properties. Depending on the type of improvement (construction of a new link, capacity addition to an existing link, or upgrading an existing link), the benefit could represent a reduction in the time cost of travel or other variable costs (fuel consumption or mileage-related vehicle depreciation). Theory would suggest that these benefits are capitalized into local property values, yielding a localized external benefit. This research will explore the nature and magnitude of such benefits. Using a sample of property sales data for Minnesota counties, both rural and urban, we will explore the impacts of upgrading roads on nearby property values. We will also attempt to track and model the cost of road upgrades considered in the sample in order to provide rough comparisons of these costs with the estimated benefits flowing from the various projects. It is also important to note that such upgrade can have a negative effect due to the external factors (e.g. noise, pollution). These factors will also be taken in the estimation of the effects of network upgrades on nearby land value.

Post-Construction Evaluation of Forecast Accuracy. Minnesota Department of Transportation
Cost: $51,832. Time: One year.

Evaluations of proposed projects and their subsequent performance depend critically on forecasts of demand made well in advance of actual implementation. Depending on the forecasting method used, there may be considerable uncertainty in projections of future benefits or other performance criteria. The current study seeks to evaluate the accuracy of demand forecasts made for a sample of recently-completed projects and estimate the impact of forecast error on post-construction measures of project performance. Data for the study will be drawn from completed environmental impact assessments, which will provide pre-construction demand forecasts, combined with recent traffic volume data from Mn/DOT. Results can be compared for urban and rural projects, as well as for different functional classes. The research will conclude with some suggestions for managing and possibly reducing uncertainty in project demand forecasts.

CAREER Award: The Evolution of Transportation Networks: Empirical Research and Agent-Based Models. National Science Foundation
Cost: $400,000. Time: Five years.

This research endeavors to understand the evolutionary growth process of transportation networks at a theoretical and empirical level, recognizing the inter-dependence of supply and demand, and to develop agent-based models to replicate that process.

The role of Social Networks and Information and Communications Technology on Destination Choice. Humphrey Institute of Public Affairs State and Local Policy Project, Techplan Program.

This research proposes to investigate the impact of traditional social networks and information and communications technology (ICT) on travelers’ destination choice. Earlier models of travel demand were aggregate in nature and found their roots in statistical mechanics rather than the behavioral basis of those decisions. Over the years advances in disaggregate modeling have led to improvements in traditional models giving them theoretical framework that related human behavior. As time has progressed, so have the models of travel demand going from the traditional four step process to disaggregate models of individual choice as widely seen in route choice models. These models by and large assume independent actors that make decisions based on their own personal taste. The extent to which social networks and information and communication technologies affect where our destinations are located is an area that is gaining more focus. This project proposes to undertake a study of the extent to which both traditional social networks and communication technologies (and social networks mediated by those technologies) affect these choices. In two phases this project hopes to develop models that incorporate important elements of social networks and ICT for different trip purposes.
One dimension of travel is that part of it is derived to engage in activities where other people, who can be friends or acquaintances, are met. Even the work trip can be thought of as an engagement where multiple people get together in a particular time slot to engage in their respective responsibilities. It has already been established that a majority of work finding occurs through weak social ties rather than through any formal search (Granovetter 1974). Recent work by the authors of this proposal on a randomly selected area of the Twin Cities observes that there is a statistically significant clustering between where individuals live and where they work. One possible explanation for this clustering is that some of the networks that lead to finding jobs may be transmitted at the neighborhood level leading to the observed clustering.
The Internet also provides a wide range of information on job availability. It is expected that a number of people find their jobs using this medium, but also that there maybe differences across sectors of the economy on its prevalence o as a tool for finding jobs. Knowing the demographic characteristics of the people who use this medium to find work, and which sectors are more likely than others to find workers using this medium allows more specific analysis than knowing only how many workers are attracted to a particular zone.
Outside of the work destined trip, it is also important to ascertain the extent to which ICT affects destination choice. Just as the Internet can be used to find jobs or organize meetings for multiple people, it is also possible that expanded access to the web has replaced the demand for face-to-face meetings and/or the requirements of travel for some activities. For example, people who want to buy a book can get more value by replacing the shopping trip to an hour on the web where they can find more information on a book from others that have read it before and more recommendation. In other cases the web can also be used to locate particular destinations for leisure, meetings or shopping. It both expands the choices for people beyond what they know of locally and can potentially replace some activities.
To answer these questions on the role of traditional social networks and ICT on destination choice, this research proposes to undertake a detailed study of employees of a particular firm where individuals are asked about the mechanisms through which they located their jobs. For example we will ask what means (e.g. recruiters, informal contacts, the web etc.) they used for finding their jobs; if contacts are used, we will ask where they are located and how information about the work reached them. By understanding the information path for different types of jobs and the systematic similarities between them, it is expected that the models of work destination can be made more specific than those done at the aggregate level.
For non-work trips, respondents will be asked how their social networks and the web affect their decisions for destinations. Some of the questions of interest are to what extent they organize meetings (both physical and virtual) over the web (limiting their network to those who have similar access), do they replace trips because of the web, do they find new destinations using the web, how in general does it affect their choices of where to shop or undertake leisure activities? Again it is expected that these considerations would lead to better and improved models that take into consideration that the people to be involved at those activities affect the destination choice in addition to the activities themselves.