Papers Presented at Conferences (when not listed elsewhere)
Hover over the article title link for abstract, click for
downloadable paper in pdf.
2012
- Huang, Arthur and Levinson, David (2012) Accessibility, network structure, and consumers’ destination choice: a GIS analysis of GPS travel data.
Anecdotal and empirical evidence has shown that road networks, destination accessibility, and travelers' choice of destination are closely related. Nevertheless, there have not been systematic investigations linking individuals' travel behavior and retail clusters at the microscopic level. Based on GPS travel data in the Twin Cities, this paper analyzes the impacts of travelers' interactions with road network structure and clustering of services at the destination on travelers' destination choice. A multinomial logit model is adopted. The results reveal that higher accessibility and diversity of services in adjacent zones of a destination are associated with greater attractiveness of a destination. Further, the diversity and accessibility of establishments in an area are often highly correlated. In terms of network structure, a destination with a more circuitous or discontinuous route dampens its appeal. Answering where and why people choose to patronize certain places, our planning, our findings shed light on the design of road networks and clusters from a travel behavior perspective. (working paper) Presented at the 91st Annual Transportation Research Board Conference. [poster]
- Iacono, Michael and David Levinson (2012) Accessibility Dynamics and Location Premia: Do Land Values Follow Accessibility Changes?.
The structure of transportation networks and the patterns of accessibility they give rise to are an important
determinant of land prices, and hence urban spatial structure. While there is ample evidence on the cross-sectional
relationship between location and land value (usually measured from the value of improved property), there is much
less evidence available on the changes in this relationship over time, especially where location is represented using
a disaggregate measure of urban accessibility. This paper provides evidence of this dynamic relationship using data
on home sales in the Minneapolis-St. Paul (MN) metropolitan area, coupled with disaggregate measures of urban
accessibility for multiple modes, for the period from 2000 to 2005. Our investigation seeks to track the effects of
marginal changes in accessibility over time, as opposed to static, cross-sectional relationships, by using an
unconventional approach in which the unit of observation is a "representative house" for each transportation
analysis zone in the region. This approach allows us to control for changes in structural attributes of houses over
time, while also isolating the effect of changes in accessibility levels. Results of this approach are compared to a
cross-sectional model using the same variables for a single year to illustrate important differences. These
differences are discussed in terms of their implications for practitioners and for further investigations of the
relationship between transportation, location and land value. (working paper) Presented at the 91st Annual Transportation Research Board Conference,
- Zhu, Shanjiang, and David Levinson (2012)
People don't use the shortest path.
Most recent route choice models, following either Random Utility Maximization or rule-based paradigm, require explicit enumeration of feasible routes. The quality of model estimation and prediction is sensitive to the appropriateness of consideration set. However, few empirical studies of revealed route characteristics have been reported in the literature. Such study could also help practitioners and researchers evaluate widely applied shortest path assumptions. This study aims at bridging the gap by evaluating morning commute routes followed by residents at the Twin Cities, Minnesota. Accurate GPS and GIS data were employed to reveal routes people utilized. Findings from this study could also provide guidance for future efforts in building better travel demand models.
JEL code: D81, D83, R41, R48, C93, D01
Keywords: Rationality, travel behavior, transport geography, commuting, transportation networks
(working paper) Presented at the 91st Annual Transportation Research Board Conference. [presentation]
2011
- Levinson, David and Bernadette Marion (2011)
The City is Flatter: Changing Patterns of Job and Labor Access in Minneapolis-Saint Paul, 1995-2005
This study describes the measurement of accessibility by automobile for the Minneapolis - Saint Paul (Twin Cities) region over the period from 1995 to 2005. In contrast to previous analyses of 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 1995 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 over this period, 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.
JEL code: R41, R48, Q41, R51
Keywords: Accessibility; Land Use; Travel Time; Travel Behavior; Twin Cities (Minnesota)
Presented at the 90th Annual Transportation Research Board Conference, January 23-27, 2011. 11-0439. Presented at the North American Regional Science Conference, Denver, CO, November 2010.
- Parthasarathi, Pavithra and David Levinson (2011)
Network Structure and Activity Spaces.
This research analyzes the influence of network structure on household spatial patterns, as measured by activity spaces. The analysis uses street network and travel survey data from the Twin Cities and South Florida to compile measures of network structure. Statistical regression models test the relationship between network structure and travel. The results show that network design does influence travel, after controlling for other non-network based measures. Results from this analysis can be used to understand how changes in network can be used to bring about desired changes in travel behavior.
JEL code: R41, R48, R53
Keywords: Transportation Geography, Network Structure, Circuity, Accessibility
Presented at the 90th Annual Transportation Research Board Conference, January 23-27, 2011. 11-3905.
- Parthasarathi, Pavithra and David Levinson (2011)
Network Structure and Metropolitan Mobility.
This research develops quantitative measures that capture various aspects of underlying network structure, using aggregate level travel data from fifty metropolitan areas across the U.S. The influence of these measures on system performance is then tested using statistical regression models. The results corroborate that the quantitative measures of network structure affect the system performance. The results from this analysis can be used to develop network design guidelines that can be used to address current transportation problems.
JEL code: R41, R48, R53
Keywords: Network structure, mobility, congestion, accessibility, travel behavior, transportation geography
Presented at the 90th Annual Transportation Research Board Conference, January 23-27, 2011. 11-3511.
2010
- Carrion, Carlos and Levinson, D. (2010), Value of Reliability: High Occupancy Toll Lanes, General Purpose Lanes, and Arterials
In the Minneapolis-St. Paul region (Twin Cities), the Minnesota Department of Transportation (MnDOT) converted the Interstate 394 High Occupancy Vehicle (HOV) lanes to High Occupancy Toll (HOT) lanes (or MnPASS Express Lanes). These lanes allow single occupancy vehicles (SOV) to access the HOV lanes by paying a fee. This fee is adjusted according to a dynamic pricing system that varies with the current demand. This paper estimates the value placed by the travelers on the HOT lanes because of improvements in travel time reliability. This value depends on how the travelers regard a route with predictable travel times (or small travel time variability) in comparison to another with unpredictable travel times (or high travel time variability). For this purpose, commuters are recruited and equipped with Global Positioning System (GPS) devices and instructed to commute for two weeks on each of three plausible alternatives between their home in the western suburbs of Minneapolis eastbound to work in downtown or the University of Minnesota: I-394 HOT lanes, I-394 General Purpose lanes (untolled), and signalized arterials close to the I-394 corridor. They are then given the opportunity to travel on their preferred route after experiencing each alternative. This revealed preference data is then analyzed using mixed logit route choice models. Three measures of reliability are explored and incorporated in the estimation of the models: standard deviation (a classical measure in the research literature); shortened right range (typically found in departure time choice models); and interquartile range (75th - 25th percentile). Each of these measures represents distinct ways about how travelers deal with different sections of reliability. In all the models, it was found that reliability was valued highly (and statistically significantly), but differently according to how it was defined. The estimated value of reliability in each of the models indicates that commuters are willing to pay a fee for a reliable route depending on how they value their reliability savings.
JEL-Code: R41, R48, D63
Keywords: time reliability, GPS, route choice, random utility, I-394 HOT, MnPass, mixed logit
Presented at 4th International Symposium on Transportation Network Reliability, July 2010, Minneapolis, MN.
- Iacono, Michael, David Levinson, and Zhirong (Jerry) Zhao (2010)
Value Capture for Transportation Finance.
As vehicles become more fuel-efficient and overall levels of travel stagnate in response to increases in fuel prices, conventional sources of revenue for transportation finance such as taxes on motor fuels have been put under increasing pressure. One potential replacement as a source of revenue is a set of policies collectively referred to as value capture policies. In contrast to fuel taxes and other instruments that impose charges on users of transportation networks, value capture policies seek to generate revenue by extracting a portion of the gains in the value of land that result from improvements to transportation networks. In this paper we identify a set of eight policies that contain elements of the value capture approach. These policies include land value taxes, tax increment financing, special assessments, transportation utility fees, development impact fees, negotiated exactions, joint development, and air rights. We evaluate each of the policies according to four criteria: efficiency, equity, sustainability (in terms of revenue adequacy and stability), and feasibility. The value capture concept is placed within a more general framework of transportation finance that emphasizes the relationship between different types of charges and groups of beneficiaries from transportation investments.
JEL code: R51, R52, R48, H23, H27, H71, R14, R21, R33
Keywords: Transportation – Economics, Land value, Transportation – finance and taxation
Presented at 89th Transportation Research Board Conference, January 2010, Washington , DC.
- Krizek, Kevin and David Levinson (2010)
Access for Performance.
This paper urges that policy decisions be based on important and reliable performance measures. Robust measures that assess the performance of the transportation and land use dimensions of cities, however, are typically missing from such discussions—they typically focus on congestion and mobility. The heart of approach suggested herein lies concept of accessibility: the ability of people to reach the destinations that they need to visit in order to meet their needs. By focusing on accessibility—rather than congestion or mobility—this approach produces a more complete and meaningful picture of metropolitan transport and land use. We place accessibility in a position of prominence as a performance measure by (a) describing the use and measurement of accessibility for metropolitan areas, (b) identifying robust, concrete and practical issues about measurement of the concept, (c) and offering prescriptions for resolving measurement issues.
JEL code: R12, R14, R41, R48, R52, R53, H11
Keywords: Accessibility, Performance Measures, Transportation, Land Use, Measures of Effectiveness.
Presented at 89th Transportation Research Board Conference, January 2010, Washington , DC.
- Tilahun, Nebiyou and David Levinson (2010)
Contacts and Meetings: Location, Duration and Distance Traveled.
The role of contacts on travel behavior has been getting increasing attention. This paper reports on data collected on individual’s social meetings and the choice of in-home/out-of-home meeting locations as well as the distance travelled and duration of out-home-meetings and its relationship to the type of contact met and other attributes of the meeting. Empirically we show that in-home meetings tend to occur most often with close contacts and less often with distant contacts. The purpose, meeting day, and household size suggest that leisure, weekend and large household size people tend to have their meetings either at their home or at their contact’s home. In addition when meetings occur outside of the house, the duration is longer for close contacts and distance to the meeting location is directly influenced by duration and indirectly by the relationship type. Overall the paper illustrates that relationship type along with other meeting specific and demographic variables is important in explaining the location, duration and distance travelled for social meetings.
JEL code: R41, D10, D85, R48
Keywords: Travel behavior, social networks, meetings, network analysis
Presented at 89th Transportation Research Board Conference, January 2010, Washington , DC.
- Zhu, Shanjiang and David Levinson (2010), A Portfolio Theory of Route Choice
Although many individual route choice models have been proposed to incorporate travel time variability as a decision factor, they are typically still deterministic in the sense that the optimal strategy requires choosing one particular route that maximizes utility. In contrast, this study introduces an individual route choice model where choosing a portfolio of routes instead of a single route is the best strategy for a rational traveler who cares about both journey time and lateness when facing stochastic network conditions. The model is then tested with GPS data collected in metropolitan Minneapolis-St. Paul, Minnesota. Our data suggest strong correlation among link speed when analyzing morning commute trips. There is no single dominant route (defined here as a route with the shortest travel time for a 15 day period) in 18% of cases when links travel times are correlated. This paper demonstrates that choosing a portfolio of routes could be the rational choice of a traveler who wants to optimize route decisions under variability.
JEL-Code: R41, R48, D63
Keywords: Transportation planning, route choice, travel behavior, link performance
Presented at 4th International Symposium on Transportation Network Reliability, July 2010, Minneapolis, MN. [poster]
- Zhu, Shanjiang and David Levinson (2010), Do people use the shortest path? An empirical test of Wardrop’s first principle.
Most recent route choice models, following either the random utility maximization or rule-based paradigm, require explicit enumeration of feasible routes. The quality of model estimation and prediction is sensitive to the appropriateness of the consideration set. However, few empirical studies of revealed route characteristics have been reported in the literature. This study evaluates widely applied shortest path assumption by evaluating morning commute routes followed by residents of the Minneapolis - St. Paul metropolitan area. Accurate GPS and GIS data were employed to reveal routes people used over an eight to thirteen week period. Most people do not choose the shortest path. Using three weeks of that data, we find that current route choice set generation algorithms do not reveal the majority of paths that individuals took. Findings from this study may provide guidance for future efforts in building better route choice models.
JEL-Code: R41, R48, D63
Keywords: Transportation planning, route choice, travel behavior, link performance
Presented at 4th International Symposium on Transportation Network Reliability, July 2010, Minneapolis, MN.
2009
2008
- Liao, Chen-Fu and David Levinson (2006) Web-Based
Roadway Geometry Design Software for Transportation Education. Traditionally,
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
- 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]
2007
- 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.
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
- 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.
- Mogush, Paul, Kevin J. Krizek, David M. Levinson (2005) Value
of Trail Access on Home Purchases. We 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 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.
2004
- Li, Ning, Xi Zou, and David Levinson (2004) Sharing
Data Between Arc/Info and Emme/2: Practice in Lyon County, Minnesota. Sharing
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 Seem. Travel
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 Roads. Transportation 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 Data. The 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 Traffic. Timely 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]
