Levinson, David M.

A well-developed methodology is crucial for both data collection and analysis, and thus the soundness of behavioral models, especially in such a limited time window. Therefore, this paper reviews both theoretical and empirical studies on traffic and behavioral impacts of network disruptions.

This synthesis reviews several strands of relevant literature that aim to assess the basic issue of the economic impact of highways.

After a long period of system deployment of the auto-highway system, and several decades of maturity of that system, the surface transportation sector is facing a large number of technological shifts that could change whether and how people travel. While nascent, their prospects are potentially significant. This research proposed to explore these technologies - ascertain their potential market, consider their interactions, understand what that might do to travel demands, and address how planning and forecasting should respond. This research developed a series of white papers: high-level policy briefs based on our analysis of each technology, its direction, and its implications for Minnesota. This work extends and complements the MnDOT 50 year vision expressed in Minnesota GO. It also builds on the ideas developed in the NCHRP 750 project: Strategic Issues Facing Transportation. The timeframe on these technologies varies, and the authors looked at deployment paths over time rather than simple snapshots in time.

Using detailed travel surveys (the Travel Behavior Inventory) conducted by the Metropolitan Council of the Minneapolis/Saint Paul (Twin Cities) Region in Minnesota for 1990, 2000-2001, and 2010-2011, this report conducts an analysis of changes in travel behavior over time. Specifically looking at changes in travel duration, time, use, and accessibility; telecommuting and its relationship with travel and residential choices; transit service quality and transit use; effects of age and cohort; and changes in walking and bicycling. Much has changed in this period, including the size of the region, demographics, economics, technology, driver licensing, and preferences, examining in turn the effects of investment, development, and population change on behaviors for the Minneapolis-St. Paul region as a whole and for areas within the region. While this research cannot hope to untangle all of the contributing factors, it aims to increase understanding of what did happen, with some explanation of why. This will inform transportation engineers, planners, economists, analysts, and decision makers about the prospective effects of future changes to networks, land use, and demographics while also evaluating the effects of previous network investments.

While High Occupancy Vehicle (HOV) lanes have been used for decades as a strategy for mitigating congestion, research has shown that they are not always effective. A 2001 study of the I-394 and I-35W HOV lanes in Minnesota found that the HOV lanes were on average underutilized, moving fewer people than the General-Purpose Lanes (GPL) even with the increased number of passengers per vehicle. To address the issue of underuse, in 2003 the Minnesota Legislature authorized the conversion of the I-394 HOV lanes into High-Occupancy Toll (HOT) lanes, named the MnPASS Express Lanes. The MnPASS lanes operate using a fully dynamic pricing schedule, where pricing is dictated by the level of congestion in the HOT lane. To better understand the nature of HOT lanes and the decisions of their users, this study explored the possibilities for a microscopic traffic simulation-based model of HOT lanes. Based on a series of field studies where the price of the toll was changed while observing changes in demand in the HOT lane, models describing the lane choice behavior of MnPASS users were developed and calibrated. These models interfaced with the traffic simulation software Aimsun through a number of extension modules and tested on the two MnPASS corridors of I-394 and I35W corridors in the west and south suburbs of Minneapolis, Minnesota. The integrated HOT simulation tool was also used to develop and test a number of alternative pricing strategies including a more efficient version of the current strategy.

This project provides case studies of the impact of transportation investments on local economies. We use multiple approaches to measure impacts since the effects of transportation projects can vary according to the size of a project and the size of the area under study, as well as other exogenous factors such as existing economic and demographic conditions. We measure effects on economic output and employment to estimate impacts of specific investments, and address issues of generative versus redistributive effects of investments, as well as identify specific economic sectors that might be disproportionately affected by such investments.

Report #13 in the series: Access to Destinations Study. This report summarizes previous phases of the Access to Destinations project and applies the techniques developed over the course of the project to conduct an evaluation of accessibility in the Twin Cities for 2010. It also describes a methodology that can be used to implement future evaluations of accessibility.

This study uses accessibility as a performance measure to evaluate a matrix of future land use and network scenarios for planning purposes. Previous research has established the coevolution of transportation and land use, demonstrated the dependence of accessibility on both, and made the case for the use of accessibility measures as a planning tool. This study builds off of these findings by demonstrating the use of accessibility-based performance measures on the Twin Cities metropolitan area. This choice of performance measure also allows for transit and highway networks to be compared side-by-side. A zone-to-zone travel time matrix was computed using Stochastic User Equilibrium (SUE) assignment with travel time feedback to trip distribution. A database of schedules was used on the transit networks to assign transit routes. This travel time data was joined with the land use data from each scenario to obtain the employment, population, and labor accessibility from each traffic analysis zone (TAZ) within specified time ranges. Tables of person-weighed accessibility were computed for 20 minutes with zone population as the weight for employment accessibility and zone employment as the weight for population and labor accessibility. The person-weighted accessibility results were then used to evaluate the planning scenarios. The results show that centralized population and employment produce the highest accessibility across all networks.

Major network disruptions have significant impacts on local travelers. A good understanding of behavioral reactions to such incidents is crucial for traffic mitigation, management, and planning. Existing research on such topics is limited. The collapse of the I-35W Mississippi River Bridge (August 1, 2007) abruptly disrupted habitual routes of about 14,000 daily trips and forced even more travelers to adapt their travel pattern to evolving network conditions. The opening of the replacement bridge on November 18, 2008 generated another disturbance (this time predictable) on the network. Such "natural" experiments provide unique opportunities for behavioral studies. This study focuses on the traffic and behavioral reactions to both bridge collapse and bridge reopening and contributes to general knowledge by identifying unique patterns following different events. Three types of data collection efforts have been conducted during the appropriate frame of reference (i.e. before vs. after bridge reconstruction): 1) GPS tracking data and associated user surveys, 2) paper and internet-based survey data gauging travel behavior in the post-bridge reconstruction phase, and 3) aggregate data relating to freeway and arterial traffic flows, traffic control, and transit ridership. Differences in reactions to planned versus unplanned events were revealed. Changes in travel cost were evaluated and their temporal and spatial patterns were analyzed. This report concludes with thorough discussions of findings from this study and policy implications.

Report #11 in the series: Access to Destinations Study. This study describes the development and application of a set of accessibility measures for the Twin Cities region that measure accessibility by the automobile mode over the period from 1995 to 2005. In contrast to previous attempts to measure accessibility this study uses travel time estimates derived, to the extent possible, from actual observations of network performance by time of day. A set of cumulative opportunity measures are computed with transportation analysis zones (TAZs) as the unit of analysis for the years 1995, 2000 and 2005. Analysis of the changes in accessibility by location over the period of study reveals that, for the majority of locations in the region, accessibility increased between 1995 and 2005, though the increases were not uniform. A "flattening"' or convergence of levels of accessibility across locations was observed over time, with faster-growing suburban locations gaining the most in terms of employment accessibility. An effort to decompose the causes of changes in accessibility into components related to transportation network structure and land use (opportunity location) reveal that both causes make a contribution to increasing accessibility, though the effects of changes to the transportation network tend to be more location-specific. Overall, the results of the study demonstrate the feasibility and relevance of using accessibility as a key performance measure to describe the regional transportation system.