Papers Presented at Conferences (when not listed elsewhere)
Hover over the article title link for abstract, click for downloadable paper in pdf.
2008
- Zhu, Shanjiang, David Levinson, and Lei Zhang (2007) An Agent-based Route Choice Model
Travel demand emerges from individual decisions. These decisions, depending on individual objectives, preferences, experiences and spatial knowledge about travel, are both heterogeneous and evolutionary. Research emerging from fields such as road pricing and ATIS requires travel demand models that are able to consider travelers with distinct attributes (value of time (VOT), willingness to pay, travel budgets, etc.) and behavioral preferences (e.g. willingness to switch routes with potential savings) in a differentiated market (by tolls and the level of service). Traditional trip-based models have difficulty in dealing with the aforementioned heterogeneity and issues such as equity. Moreover, the role of spatial information, which has significant influence on decision-making and travel behavior, has not been fully addressed in existing models. To bridge the gap, this paper proposes to explicitly model the formation and spreading of spatial knowledge among travelers. An Agent-based Route Choice (ARC) model was developed to track choices of each individual decision-maker in a road network over time and map individual choices into macroscopic flow pattern. ARC has been applied on both Sioux Falls network and Chicago sketch network. Comparison between ARC and existing models (UE and SUE) on both networks shows ARC is valid and computationally tractable. To be brief, this paper specifically focuses on the route choice behavior, while the proposed model can be extended to other modules of travel demand under an integrated framework.
. Presented at 87th Transportation Research Board Conference, January 2008, Washington , DC. #08-2152 [poster]
- Liao, Chen-Fu and David Levinson (2006) Web-Based Roadway Geometry Design Software for Transportation EducationTraditionally, students use pencil and ruler to lay out lines and curves over contour maps for roadway geometry design. Numerous calculations of stopping sight distance, minimum turning radius, and curve alignments are required during the roadway design process in order to ensure safety, to minimize economic and environmental impacts, as well as to reduce construction costs. Iterative computations during the design process are usually performed manually by the students in order to meet any given design criteria and environmental constraints. The traditional design process of roadway geometry design is often cumbersome and time consuming. It limits students from taking a broader perspective on the overall roadway design process. An Internet-based roadway design tool (ROAD: Roadway Online Application for Design) was developed to enhance the learning experience for transportation engineering students. This tool allows students to efficiently design and to easily modify the roadway design with given economic and environmental parameters. A 3D roadway geometry model can be generated by the software at final design to allow students immerse themselves in the driver’s seat and drive through the designed roadway at maximum design speed. This roadway geometry design tool was deployed and tested in a civil engineering undergraduate class in spring 2006 at University of Minnesota, Department of Civil Engineering. Feedback was collected from instructors and students that will lead to additional enhancements of the roadway design software.
Keywords: Roadway Geometry Design, Distance Learning, Transportation Visualization Presented at 87th Transportation Research Board Conference, January 2008, Washington , DC. #08-0042
2007
- Tilahun, Nebiyou and David Levinson (2007) Work and Home Location: Possible Role of Social Networks This research explores to what extent people’s work locations are similar to that of those who live around them. Using the Longitudinal Economic and Household Dynamics data set and the US census for the Twin Cities (Minneapolis-St. Paul) metropolitan area, we investigate the home and work locations of different census block residents. Our aim is to investigate if people who live close to one another, also work close to one another to a degree beyond what would be expected at random. We find a significantly non-random correlation between joint home and joint work locations. Further, we show what features of particular neighborhoods are associated with comparatively higher incidences of people sharing work locations. One reason for such an outcome can be the role neighborhood level social networks play in locating jobs; or conversely work place social networks play in choosing the home location or both. Such findings should be used to refine work trip distribution models that otherwise depend mainly on impedance between the origin and destination.
Presented at Frontiers in Transportation: Social Interactions: 14-16 October 2007 and Transportation Research Board Conference, January 2008.
- Tilahun, Nebiyou and David Levinson (2007) Value of Time Comparisons in the Presence of Unexpected Delay.This study estimates Value of Time differences between people who arrived at their destination
as planned and those that were delayed. The analysis is based on the I-394 MnPASS High
Occupancy/Toll (HOT) lane project recently implemented in the Minneapolis/St. Paul region.
Using a Stated Preference survey, the individuals are asked about a trip they have taken before,
and asked if they would opt for the free route or pay and go on the HOT lanes. The analysis
groups the travelers into subscribers and non-subscribers of the MnPASS (electronic toll
collection transponder) system and further decomposes choices into categories based on trip time
and experience (delayed or not). Trip times were divided into morning peak, afternoon peak, and
off peak and trip experience was divided into delayed and not delayed, creating six categories.
The findings suggest an increased willingness to pay among subscribers who were late to reduce
travel time in the PM rush hour. As well, we find some evidence that individuals who were late
during the AM peak have a lower VOT as compared to their on-time counterparts. Presented at the Third International Conference on Transport Network Reliability in Delft, Netherlands, July 2007
- Zhang, Lei, David Levinson, and Shanjiang Zhu (2007) Agent-Based Model of Price Competition and Product Differentiation on Congested Networks.Abstract: Using consistent agent-based techniques, this research models the decision-making
processes of users and infrastructure owner/operators to explore the welfare consequence
of price competition, capacity choice, and product differentiation on congested
transportation networks. Component models include: (1) An agent-based travel demand
model wherein each traveler has learning capabilities and unique characteristics (e.g.
value of time); (2) Econometric facility provision cost models; and (3) Representations of
road authorities making pricing and capacity decisions. Different from small-network
equilibrium models in prior literature, this agent-based model is applicable to pricing and
investment analyses on large complex networks. The subsequent economic analysis
focuses on the source, evolution, measurement, and impact of product differentiation with
heterogeneous users on a mixed ownership network (with tolled and untolled roads). Two
types of product differentiation in the presence of toll roads, path differentiation and
space differentiation, are defined and measured for a base case and several variants with
different types of price and capacity competition and with various degrees of user
heterogeneity. The findings favor a fixed-rate road pricing policy compared to complete
pricing freedom on toll roads. It is also shown that the relationship between net social
benefit and user heterogeneity is not monotonic on a complex network with toll roads. Presented at the World Conference on Transport Research in Berkeley, California June 24-28 2007.
- King, David, Kevin Krizek, and David Levinson (2007) Air Rights: a teaching laboratory for an integrated land use and transportation planning course The intersection of land use and transportation policy is becoming an increasingly important focus for all urban planners. This focus, however, challenges the academic community to design effective courses that teach the concepts and professional skills required for professional experience. Integrated land use and transportation courses should engage students to develop interdisciplinary skills while becoming familiar with, for example, travel behavior and zoning policies. Laboratory courses (or segments of courses) as part of graduate curricula provide platforms to further emphasize skills. A common pedagogy problem is devising laboratory assignments that are integrative, cumulative, practical, and interesting for students. Furthermore, laboratory projects should introduce students to real-world problems and techniques while exploring broad planning themes.
This paper presents uses four years of laboratory segments from a land use-transportation course (LUTC) at the University of Minnesota to evaluate the needs and results of practitioner-oriented land use and transportation planning education. The laboratory used group projects where students proposed integrated developments using air rights above existing (and sunken) urban freeways in the Twin Cities. The projects provided a practitioner-oriented project through a collaborative and reflexive learning process. This article describes the completed projects, as well as the technical skills, integrated approach and visionary planning necessary for successful execution. The students addressed complicated problems associated with large-scale development by researching neighborhood demographics, characteristics, and pertinent regulations. They used their research to analyze traffic impacts, propose zoning regulations, and outline costs and benefits from their proposal using Geographic Information Systems (GIS), statistical analyses, assessor data and traffic engineering manuals. Using the completed student projects and comparisons with other land use-transportation course and laboratory projects the authors demonstrate how these laboratory components serve multiple pedagogy goals.
Keywords: Air Rights, Transportation-Land Use Planning, Education presented at the 86th Annual Meeting of the Transportation Research Board in Washington, DC, January 21-25 2007. [TRB Paper #(07-2496)]
- Corbett, Michael, Feng Xie, and David Levinson (2007) Evolution of the Second-Story City: The Minneapolis Skyway SystemThis paper describes and explains the growth of the Minneapolis Skyway network. Accessibility is used as a major factor in understanding that growth (i.e. does the network connect to the location(s) with the highest accessibility, followed by the second highest, and so on). First, employment opportunities are used as the measure of activity and are based off of the square footage of buildings and/or ITE trip generation rates. Using information about the buildings located downtown for each year since the first skyway was built, the accessibilities of each of the connected and adjacent unconnected blocks were calculated for every time period the skyway system expanded. The purpose is to determine how often the expansion connected the block with the highest accessibility. The results show that though important, accessibility was rarely maximized, except in the early stages of development. A connect-choice logit model relating the probability of joining the network (in a given year) to accessibility and network size was employed. The results show accessibility does remain an important factor in predicting which links are connected. Physical difficulties in making connections may have played a role, as well as the potential for adverse economic impacts.
Keywords: Network growth, Skyways, Minneapolis Presented at the 2007 World Conference on Transportation Research.
- Wasfi, Rania A., David Levinson and Ahmed M. El-Geneidy, (2007) The Transportation Needs of SeniorsOver 208,000 residents of Hennepin County, Minnesota are over the age of 55, a number that is sure to rise. This paper examines the transportation needs of the elderly in Hennepin County through a mail out-mail back survey of their existing travel behavior and their unmet needs. The survey had both demographic and attitude questions as well as a travel diary for recording actual trips and desired but untaken trips. We found that 87% of the sampled population feel they are independent travelers. Around 51 percent of the surveyed population indicated that they are transit users, 25 percent of them revealed their concerns about difficulties they are facing when using public transit. About 16 percent of transit users were concerned about waiting time for transit, while only 8% were concerned about the travel time. Only 15 percent of the surveyed population use paratransit. A large number of comments were received, which add qualitative flavor to the analysis that was conducted. Seniors recognize even if they are currently independent, that will not always be the case, and acknowledge they should plan.
Keywords: Transportation needs, Elderly, Seniors, Disadvantaged Populations Presented at the 2007 World Conference on Transportation Research.
- Wasfi, Rania A., David Levinson and Ahmed M. El-Geneidy, (2007) Measuring the transportation needs of people with developmental disability The US Department of Health and Human Services Administration on Development Disabilities estimates the number of people diagnosed with a developmental disability in the United States as 4.5 million persons, which would translate to about 17,000 residents of Hennepin County, Minnesota. This research paper examines the transportation needs of adults with developmental disabilities either residing or working in Hennepin County through a survey of their existing travel behavior and their unmet transportation needs. The survey had both demographic and attitude questions as well as a travel diary to record both actual and desired but untaken trips. In this paper we report and discuss the main findings of the survey. It was clear from observing the returned sample that almost the entire surveyed population does not live independently. More than half of the surveyed population worked every day, while recreation occurred at least once a week for about two-thirds of the population, and more than half undertook social trips weekly. About 30% reported being unable to make trips they want to make and 46% unable to make trips they need to make. Public transit poses difficulties for this population both physically and intellectually. There were also specific complaints about the lack of transit service in addition to concerns regarding paratransit services. Community service providers received praise.
Keywords: Developmental disability, disadvantaged population, disability, transportation needs presented at the 2007 Transportation Research Board Conference.
- Zhu, Shanjiang, Feng Xie and David Levinson (2006) Enhancing Transportation Education through On-line Simulation using an Agent-Based Demand and Assignment ModelThis research explores the effectiveness of using simulation as a tool for enhancing classroom learning in the Civil Engineering Department of the University of Minnesota at Twin Cities. The authors developed a modern transportation planning software package, Agent-based Demand and Assignment Model (ADAM), that is consistent with our present understanding of travel behavior, that is platform independent, and that is easy to learn and is thus usable by students. An in-class project incorporated ADAM and the performance of this education strategy was evaluated through pre-class survey, post-class survey, scores in the quiz focusing on travel demand modeling and final scores. Results showed that ADAM effectively enhanced students' self-reported understanding of transportation planning and their skills of forming opinions, evaluating projects and making judgments. Students of some learning styles were found to benefit more than others through simulation-based teaching strategy. Findings in this research could have significant implications for future practice of simulation-based teaching strategy.
Keywords: Agent-based Model, Transportation Education, Simulation presented at the 2007 Transportation Research Board Conference.
- Xie, Feng and David Levinson (2005)
The Topological Evolution of Road Networks Road networks evolve into different topologies over time. This study explores the topological evolution of a road network employing a simulation model that incorporates exogenous input, degeneration, land use dynamics, travel demand dynamics, and investment. The model is implemented and the network topologies are visualized with a
java-based simulator.
Starting with idealized networks with different geometrical features and symmetry
conditions, eight experiments incorporate specified degeneration criteria to remove the
weakest link(s) from test networks iteratively as they evolve, resulting in various network
topologies during this process. Selected topological measures are computed throughout
to track the topological evolution of test networks.
Results demonstrate that typical topologies of road networks like rings and hub-and-
spokes emerge over time even based on completely decentralized decisions of
autonomous roads, and that an emergent topology of a road network has a certain insensitivity to various initial conditions. These results provide evidence for the claim
that the topology of a road network is an emergent property of network evolution.
Keywords: road network, evolution, topology, degeneration, simulation presented at the 2007 Transportation Research Board Conference.
- Levinson, David and Ahmed El-Geneidy (2007) Network Circuity and the Location of Home and WorkIn an urban context people travel between places of residence and work
destinations via transportation networks. Transportation studies that
involve measurements of distances between residence and work locations
tend to use Euclidean distances rather than Network distances. This is
due to the historic difficulty in calculating network distances and based
on assumptions that differences between Euclidean distance and network
distance tend to be constant. This assumption is true only when variation
in the network is minor and when self-selection is not present. In this
paper we use circuity, the ratio of network to Euclidean distance, as
a tool to better understand the choice of residential location relative
to work. This is done using two methods of defining origins and destinations
in the Twin Cities metropolitan region. The first method of selection
is based on actual choice of residence and work locations. The second
is based on a randomly selected dataset of origins and destinations in
the same region. The findings of the study show circuity measured through
randomly selected origins and destinations differ from circuity measured
from actual origins and destinations. Workers tend to reside in areas
where the circuity is lower, applying intelligence to their location decisions.
We posit this because locators wish to achieve the largest residential
lot at the shortest commute time. This finding reveals an important issue
related to resident choice and location theory and how resident workers
tend to locate in an urban context.
Keywords: Network structure, travel behavior, transport geography, commuting, circuity presented at the UTSG Conference.
2006
- Tilahun, Nebiyou, and David Levinson (2006) Selfishness and Altruism in the Distribution of Travel Time and Income Most economic models assume that individuals act out their preferences based on their
own self interest. However there have also been other paradigms in the economics
literature that have tried to capture alternative manifestations of human behavior that
include fairness. This study examines people's preferences when it comes to their travel
time and their income and what type of trade offs they are willing to make to live in a
society where the distributions of travel time and income are fairer. Using a stated
preference experiment we find that when it comes to travel time, individuals are more
concerned with societal average travel time, followed by their own travel time and finally
by large inequalities in the society, while in the case of income they are more concerned
with their own income, followed by societal average and finally by inequality.
Keywords:
Fairness, Inequality, Travel Time, Income, Altruism, Stated Preference, Veil of
ignorance, Equity, Time equity, Income Equity, Time distribution, Income Distribution. presented at the 11th International Association of Travel Behaviour Research Conference in Kyoto, Japan August 16-20, 2006 [presentation]
2005
- Mogush, Paul,
Kevin J. Krizek,
David M. Levinson (2005) Value of Trail Access on Home PurchasesWe use hedonic analysis of home sales data from the Twin Cities Metropolitan Area to estimate the
effects of access of different types of trails on home value. Our model includes proximity to three distinct
types bicycle facilities, controlling for local fixed effects and open space characteristics. Using interaction
terms detect different preferences between city and suburban homebuyers. Regression results show that
off-street bicycle trails situated alongside busy streets are negatively associated with home sale prices in
both the city and suburbs. Proximity to off-street bicycle trails away from trafficked streets in the city are
positively associated with home sale prices, with no significant result in the suburbs. On-street bicycle
lanes have no effect in the city and are a disamenity in the suburbs.
The following policy issues are relevant from this research. First, type of trail matters. On-street trails and
road-side trails may not be as appreciated as many city planners or policy officials think. Second, city
residents have different preferences than suburban residents. Third and as suspected, larger and more
pressing factors likely influencing residential location decisions. The finding also suggest that urban
planners and advocates need to be aware of the consequences of providing for bicycle facilities, as the
change in welfare is not necessarily positive for all homeowners. (05-0975)
presented at 84th Annual Meeting of Transportation Research Board in Washington, DC, January 9-13th 2005.
- Zhang, Lei, Feng Xie, David M. Levinson (2005) Variation of Subjective Value of Travel Time on Freeways and Ramp MetersThis paper explores drivers' subjective value of time under moving and stopped freeway travel
conditions using a stated preference survey. Unlike previous studies that assume a constant value
of time, this research relates perceived satisfaction of a freeway trip to its quality indicators.
Sixty-nine subjects in the Twin Cities are asked in the survey to rank sixteen driving scenarios in
four condition sets with different durations of ramp wait and freeway travel. Several utility
functions are specified where the weight of ramp delay is a function of the length of the delay
itself and subject specific variables, and the resulting choice models estimated using rank-ordered logit and binary logit techniques. Results suggest that drivers perceive ramp wait as
more onerous than freeway travel. Drivers also weight each minute of ramp wait more heavily as
the length of the delay gets longer. Although the subjects show some tolerance to the first
several minutes of ramp delay (less than 5 minutes), they perceive long delays as much as twelve
times more onerous than time in motion. The derived weighting function for ramp wait can
improve the design of freeway traffic control strategies that trade-off freeway delay with ramp
wait. The findings also enable a more utility-based approach for freeway operations than the
current method which has the engineering efficiency objective of minimizing total system delay
or maximizing throughput. Minimizing total perceived travel time is probably more appropriate
than minimizing total absolute travel time which does not take into account driver acceptance.
The weighting function can also be easily transformed into a value of time function for project
evaluation purposes.
Keywords: Value of time, value of travel time, Time perception, Driver acceptance, Freeway
congestion, Ramp meter (05-0868)
presented at 84th Annual Meeting of Transportation Research Board in Washington, DC, January 9-13th 2005.
- Zhang, Lei and David M. Levinson (2005) Pricing, Investment, and Network Equilibrium Despite rapidly emerging innovative road pricing and investment principles, the development
of a long run network dynamics model for necessary policy evaluation is still lagging. This
research endeavors to fill this gap and models the impacts of road financing policies
throughout the network equilibration process. The manner in which pricing and investment
jointly shape network equilibrium is particularly important and explored in this study. The
interactions among travel demand, road supply, revenue mechanism and investment rules are
modeled at the link level in a network growth simulator. After assessing several measures of
effectiveness, the proposed network growth model is able to evaluate the short- and long-run
impacts of a broad spectrum of road pricing and investment policies on large-scale road
networks, which can provide valuable information to decision-makers such as the
implications of various policy scenarios on social welfare, financial situation of road
authorities and potential implementation problems. Some issues hard to address in theoretical
analysis can be examined in the agent-based simulation model. As a demonstration, we apply
the network growth model to assess marginal and average pricing scenarios on a sample
network. Even this relatively simple application provides new insights into issues around road
pricing that have not previously been seriously considered. For instance, the results disclose a
potential problem of over-investment when the marginal cost pricing scheme is adopted in
conjunction with a myopic profit-neutral investment policy.
Keywords: Transportation network equilibrium; Road growth; Pricing; Congestion toll;
Investment; Transport policy analysis. (05-0943)
presented at 84th Annual Meeting of Transportation Research Board in Washington, DC, January 9-13th 2005.
- Li, Ning, David M. Levinson, Brian Smalkoski, and Michael Corbett (2005) Benefit-Cost Analysis of Spring Weight Restrictions in Lyon County, Minnesota Spring Weight Restrictions (SWR) forbid heavy trucks to run on some low-
level roads during the spring thaw period. There has been long dispute between
trucking industry and road agencies on the effectiveness of this policy. Previous
studies showed inconsistent results on this issue. This paper consistently estimates the
benefits and costs of the SWR policy in Lyon County, Minnesota. A freight demand
model was built to simulate truck flow on the road network. A pavement performance
model estimates pavement life in terms of rutting failure based on the traffic provided
by freight demand model. The analysis shows that the benefits of SWR to local
agencies are exceeded by the costs to truckers, which suggests lifting these seasonal
restrictions on 7 and 9-ton roads.
Keywords:
Spring Weight Restrictions, Spring Load Restrictions, Benefit/Cost Analysis,
EMME/2, Freight Demand Model, Pavement Performance Model, Freight Economics,
Truck Weight Restrictions (05-1495) presented at 84th Annual Meeting of Transportation Research Board in Washington, DC, January 9-13th 2005.
2004
- Ning Li, Xi Zou, and David Levinson (2004) Sharing Data Between Arc/Info and Emme/2: Practice in Lyon County, MinnesotaSharing data between GIS software (Arc/Info) and Traffic Demand Modeling Software (EMME/2) has long been an issue of interest to traffic engineers. A literature review and evaluation of current efforts on the data exchange is given in this paper. The authors also developed their own economical method to realize the data transform through Matlab programming. As an example, the road network of Lyon County, Minnesota is constructed by the integrated use of Arc/Info, EMME/2, Enif, and the Matlab program. The combined use of these programs achieved the expected objectives through a practical and economical way. The method can be utilized by other EMME/2 users who have a similar need.
Keywords: Data exchange, Emme/2, Arc/info, network map presented at 45th Transportation Research Forum Annual Meeting
- Muthuswamy, Satyanarayana, Gary A Davis, David M Levinson and Panos G Michalopoulos (2004) Freeway Origin Destination Matrices: Not as Simple as They SeemTravel demand can be elegantly represented using
an Origin-Destination (OD) matrix. The link counts observed on the network
are produced by the underlying travel demand. One could use these counts
to reconstruct the OD matrix. An offline approach to estimate a static
OD matrix over the peak period for freeway sections using these counts
is proposed in this research. Almost all the offline methods use linear
models to approximate the relationship between the on-ramp and off-ramp
counts. Previous work indicates that the use of a traffic flow model embedded
in a search routine performs better than these linear models. In this
research that approach is enhanced using a microscopic traffic simulator,
AIMSUN, and a gradient based optimization routine, MINOS, interfaced to
estimate an OD matrix. This approach is an application of the Prediction
Error Minimization (PEM) method. The problem is non-linear and non-smooth,
and the optimization routine finds multiple local minima, but cannot guarantee
a global minima. However, with a number of starting seed matrices,
an OD matrix with a good fit in terms of reproducing traffic counts can
be estimated. The dominance of the mainline counts in the OD estimation
and an identifiability issue is indicated from the experiments. The quality
of the estimates improves as the specification error, introduced due to
the discrepancy between the traffic flow model and the real world process
that generates the on-ramp and off-ramp counts, reduces.
Keywords: travel demand, OD estimation, simulation, optimization presented at Transportation Research Board 83rd Annual Meeting, January 10-14 2004, Washington DC [poster]
- Zhang, Lei and David Levinson (2004) A Model of the Rise and Fall of RoadsTransportation network planning decisions made at one point of time can have profound impacts in the future. However, transportation networks are usually assumed tobe static in models of land use. A better understanding of the natural growth pattern of roads will provide valuable guidance to planners who try to shape the future network. This paper analyzes the relationships between network supply and travel demand, and describes a road development and degeneration mechanism microscopically at the linklevel. A simulation model of transportation network dynamics is developed, involving iterative evolution of travel demand patterns, network revenue policies, cost estimation,and investment rules. The model is applied to a real-world congesting network-the Twin Cities transportation network which comprises nearly 8,000 nodes and more than 20,000 links, using network data collected since year 1978. Four experiments are carried out with different initial conditions and constraints, the results from which allow us toexplore model properties such as computational feasibility, qualitative implications, potential calibration procedures, and predictive value. The hypothesis that roadhierarchies are emergen properties of transportation networks is confirmed, and the underlying reasons discovered. Spatial distribution of capacity, traffic flow, andcongestion in the transportation network is tracked over time. Potential improvements to the model in particular and future research directions in transportation network dynamicsin general are also discussed.
Keywords: Transportation network dynamics, Urban planning, Road supply presented March 2004 at MIT Engineering Systems Symposium
2003
- Levinson, D and Hong Huo(2003), Effectiveness of VMS Using Empirical Loop Detector DataThe effectiveness of Variable Messages Signs (VMS) on route guidance is assessed by a discrete probit choice model that estimates the proportion of vehicles that diverts to an alternative routes given the characteristics of different messages. A before-and-after study is also conducted to quantitatively evaluate the network wide reduction of travel time and total delay of VMS systems. We find that VMS has no obvious effect on reduction of travel time, but can reduce the total delay.
Keywords: Variable message signs (VMS), Route Choice, Diversion Behavior,
Cost Benefit Analysis presented at Transportation Research Board Conference, January 12 –
16 2003 Washington DC (Session 565)
- Zou, Xi and David Levinson (2003), Detecting the Breakdown of TrafficTimely traffic prediction is important in advanced traffic management systems to make possible rapid and effective response by traffic control facilities. From the observations of traffic flow, the time series present repetitive or regular behavior over time that distinguishes time series analysis of traffic flow from classical statistics, which assumes independence over time. By taking advantage of tools in frequency domain analysis, this paper proposes a new criterion function that can detect the onset of congestion. It is found that the changing rate of the cross-correlation between density dynamics and flow rate determines traffic transferring from free flow phase to the congestion phase. A definition of traffic stability is proposed based on the criterion function. The new method suggests that an unreturnable transition will occur only if the changing rate of the cross-correlation exceeds a threshold. Based on real traffic data, detection of congestion is conducted in which the new scheme performs well compared to previous studies. presented
at Transportation Research Board Conference, January 12 –– 16
2003 Washington DC (Session 732) (03-2153)
2002
- Levinson, David (2002) Road Pricing and Compensation for Delay The equity issues facing congestion pricing are deep and a major impediment to its adoption. A criticism that gets very little attention is that not only does a toll road enable some to buy their way out of congestion, they often do so at the expense of others - that is, they may make others wait longer so that they can avoid delay. They, along with the toll road authority, are in a sense stealing time from those who don't pay. What to do with the revenue from congestion pricing is a critical question that needs to be answered before toll roads will become widely adopted. This paper investigates the issue of compensation and several possible alternatives. The equity and efficiency problem of conventional (uncompensated) congestion pricing is outlined. Then several of the previous alternatives are discussed and developed. A new compensation mechanism is suggested, called the "delayer pays" principle. This principle ensures that those who are undelayed but delay others pay a toll to compensate those who are delayed. Issues of imperfect information and gaming the system are addressed. Such a system can potentially eliminate some of the disadvantages of congestion pricing while ensuring that the money stays within the transportation sector.
Key Words: Value Pricing, Road Pricing, Compensation, Transportation Equity
presented at Transportation Research Board Conference, January 14-18 2002, Washington DC (02-2017) Published in Levinson, David (2002) Financing Transportation Networks. Edward Elgar Publishers, Northampton, Massachusetts [presentation]
