Few empirical studies of revealed route characteristics have been reported in the literature. This study challenges the widely applied shortest-path assumption by evaluating routes followed by residents of the Minneapolis–St. Paul metropolitan area, as measured by the GPS Component of the 2010 Twin Cities Travel Behavior Inventory conducted by the Metropolitan Council. It finds that most travelers used paths longer than the shortest path. This is in part a function of trip distance, trip circuity, number of turns, and age of the driver. Some reasons for these findings are conjectured.
Abstract: In a stochastic roadway congestion and pricing model, one scheme (omniscient pricing) relies on the full knowledge of each individual journey cost and of early and late penalties of the traveler. A second scheme (observable pricing) is based on observed queuing delays only. Travelers are characterized by late-acceptance levels. The effects of various late-acceptance levels on congestion patterns with and without pricing are compared through simulations. The omniscient pricing scheme is most effective in suppressing the congestion at peak hours and in distributing travel demands over a longer time horizon. Heterogeneity of travelers reduces congestion when pricing is imposed, and congestion pricing becomes more effective when cost structures are diversified rather than identical. Omniscient pricing better reduces the expected total social cost; however, more travelers improve welfare individually with observable pricing. The benefits of a pricing scheme depend on travelers’ cost structures and on the proportion of late-tolerant, late-averse, and late-neutral travelers in the population.
Keywords: commute, congestion pricing, omniscient and observable pricing schemes, road pricing, second-best pricing, social cost and individual welfare, stochastic network equilibrium, traveler departure patterns
(Personal note. This paper was first submitted in 2005. Revised and accepted in 2007, and published in 2015. Sadly this tops my previous record for the longest a paper has taken, which had gone to Ramp Metering and Freeway Bottleneck Capacity at 7 years. My thanks to my co-author for his infinite patience. However, this is theory, rather than empirical, and so we have not been trumped by other research.)
Using detailed travel surveys conducted by the Metropolitan Council of the Minneapolis/Saint Paul region for 1990, 2000-2001, and 2010-2011, this study analyses journey-to- work times, activity allocation and accessibility. The analysis shows a decline in the time people spend outside of their homes as well as the time people spend in travel over the past decade. Although distances per trip are increasing, the willingness to make trips is declining, resulting in fewer kilometers traveled and less time allocated to travel. This study finds accessibility to be a significant factor in commute durations. Accessibility and commute duration have large effects on the amount of time spent at work therefore activity patterns are influenced by transportation and the urban environment.
In 1863, the Metropolitan Railway of what came to be known as the London Underground successfully opened as the world’s first subway. Its high ridership spawned interest in additional links. Entrepreneurs secured funding and then proposed new lines to Parliament for approval, though only a portion were actually approved. While putative rail barons may have conducted some economic analysis, the final decision lay with Parliament, which did not have available modern transportation economic or geographic analysis tools. How good were the decisions that Parliament made in approving Underground Lines? This paper explores the role accessibility played on the decision to approve or reject proposed early London Tube Schemes.
Abstract: The replacement I-35W bridge in Minneapolis saw less traffic than the original bridge though it provided substantial travel time saving for many travelers. This observation cannot be explained by the classical route choice assumption that travelers always take the shortest path. Accordingly, a boundedly rational route switching model is proposed assuming that travelers will not switch to the new bridge unless travel time saving goes beyond a threshold or “indifference band”. To validate the boundedly rational route switching assumption, route choices of 78 subjects from a GPS travel behavior study were analyzed before and after the addition of the new I-35W bridge. Indifference bands are estimated for both commuters who were previously bridge users and those who never had the experience of using the old bridge. This study offers the first empirical estimation of bounded rationality parameters from GPS data and provides guidelines for traffic assignment.
Keywords: Route Choice, Travel Demand Modeling, Bounded Rationality, Indifference Band, GPS Study, Travel Behavior, Networks
High Occupancy/Toll (HOT) Lanes typically charge a varying to single occupant vehicles (SOVs), with the toll increasing during more congested periods. The toll is usually tied to time of day or to the density of vehicles in the HOT lane. The purpose of raising the toll with congestion is to discourage demand enough to maintain a high level of service (LOS) in the HOT lane. Janson and Levinson (2014) demonstrated that the HOT toll may act as a signal of downstream congestion (in both general purpose (GP) and HOT lanes), causing an increase in demand for the HOT lane, at least at lower prices. This paper builds off that research and explores alternative HOT lane pricing strategies, including the use of GP density as a factor in price to more accurately reflect the value of the HOT lane. In addition, the paper explores the potential effect these strategies would have on the HOT lane vehicle share through a partial equilibrium analysis. This analysis demonstrates the change in demand elasticity with price, showing the point at which drivers switch from a positive to negative elasticity.
Abstract: In 1863, the Metropolitan Railway of what came to be known as the London Underground successfully opened as the world’s first subway. Its high ridership spawned interest in additional links. Entrepreneurs secured funding and then proposed new lines to Parliament for approval, though only a portion were actually approved. While putative rail barons may have conducted some economic analysis, the final decision lay with Parliament, which did not have available modern transportation economic or geographic analysis tools. How good were the decisions that Parliament made in approving Underground Lines? This paper explores the role accessibility played on the decision to approve or reject proposed early London Tube Schemes. It finds that maximizing accessibility to population (highly correlated with revenue and ridership) largely explains Parliamentary approvals and rejections.
Keywords: Accessibility, Network Growth, Subways, Public Transport, Travel Behavior, Networks
This paper discusses the development of a national public transit accessibility evaluation framework, focusing on lessons learned, data source evaluation and selection, calculation methodology, and examples of accessibility evaluation results. In both practice and in research, accessibility evaluation remains experimental and methodologically fragmented. This heightens the “first mover” risk for agencies seeking to implement accessibility-based planning practices, as they must select a method which might produce results that can only be interpreted locally. Development of a common baseline accessibility metric could advance the use of accessibility- based planning. The accessibility evaluation framework described here builds on methods developed in earlier project, extended for use on a national scale and at the Census block level. Application on a national scale involves assembling and processing a comprehensive national database of public transit network topology and travel times. This database incorporates the significant computational advancement of calculating accessibility continuously for every minute within a departure time window of interest. Values for contiguous departure time spans can then be averaged or analyzed for variance over time. This significantly increases computational complexity, but provides a very robust representation of the interaction between transit service frequency and accessibility at multiple departure times.
Janson, M. and Levinson, D. (2014) HOT or not: Driver elasticity to price on the MnPASS HOT lanes. Research in Transportation Economics. [doi] (preprint)
The Minnesota Department of Transportation (MnDOT) has added MnPASS High Occupancy Toll (HOT) lanes on two freeway corridors in the Twin Cities. While not the first HOT lanes in the country, the MnPASS lanes are the first implementation of road pricing in Minnesota and possess a dynamic pricing schedule. Tolls charged to single occupant vehicles (SOVs) are adjusted every 3 min according to HOT lane vehicle density. Given the infancy of systems like MnPASS, questions remain about drivers’ responses to toll prices. Three field experiments were conducted on the corridors during which prices were changed. Data from the field experiments as well as two years of toll and traffic data were analyzed to measure driver responses to pricing changes. Driver elasticity to price was positive with magnitudes less than 1.0. This positive relationship between price and demand is in contrast with the previously held belief that raising the price would discourage demand. In addition, drivers consistently paid between approximately $60–120 per hour of travel time savings, much higher than the average value of time. Reasons for these results is discussed as well as the implications these results have on the pricing of HOT lanes.