Relationship between mean and day-to-day variation in travel time in urban networks

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The day-to-day reliability of transportation facilities significantly affects travel behavior. To better understand how travelers use these facilities, it is critical to understand and characterize this reliability for different facilities. Early work in this area assumed that the variance of day-to-day travel times (a measure of the inverse of reliability) increases proportionally with the mean travel time; i.e., as the mean travel time increases, travel time reliability decreases. However, recent empirical data for a single bottleneck facility and a small urban network suggest a more complex relationship that exhibits hysteresis. When this phenomenon is present, the variance in travel time is larger as the mean travel time decreases (congestion recovery) than as the mean travel time increases (congestion onset). This paper presents an elegant theoretical model to describe the variance of travel times across many days in an urban network. This formulation shows that the hysteresis behavior observed in empirical floating car data on urban networks should not be unexpected, and that it is linked to the hysteresis loops that often exist in the Macroscopic Fundamental Diagram of urban traffic. To verify the validity of this formulation, data from a micro-simulation of the City of Orlando, Florida, are used to derive an observed relationship with which to compare to theory. The simulated data are shown to match the theoretical predictions very well, and confirm the existence of hysteresis in the relationship between the mean and variance of travel times that is suggested by theory. These results can be used as a first step to more accurately represent travel time reliability in future models of traveler decision-making.

Original languageEnglish (US)
Pages (from-to)227-243
Number of pages17
JournalEURO Journal on Transportation and Logistics
Volume3
Issue number3-4
DOIs
StatePublished - Oct 1 2014

Fingerprint

Travel Time
Travel time
travel
hysteresis
Hysteresis
Congestion
Relationships
time
Urban networks
Microsimulation
Fundamental Diagram
Decrease
Urban Traffic
Hysteresis Loop
Formulation
travel behavior
floating
Hysteresis loops
Theoretical Model
Railroad cars

All Science Journal Classification (ASJC) codes

  • Modeling and Simulation
  • Transportation
  • Management Science and Operations Research

Cite this

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abstract = "The day-to-day reliability of transportation facilities significantly affects travel behavior. To better understand how travelers use these facilities, it is critical to understand and characterize this reliability for different facilities. Early work in this area assumed that the variance of day-to-day travel times (a measure of the inverse of reliability) increases proportionally with the mean travel time; i.e., as the mean travel time increases, travel time reliability decreases. However, recent empirical data for a single bottleneck facility and a small urban network suggest a more complex relationship that exhibits hysteresis. When this phenomenon is present, the variance in travel time is larger as the mean travel time decreases (congestion recovery) than as the mean travel time increases (congestion onset). This paper presents an elegant theoretical model to describe the variance of travel times across many days in an urban network. This formulation shows that the hysteresis behavior observed in empirical floating car data on urban networks should not be unexpected, and that it is linked to the hysteresis loops that often exist in the Macroscopic Fundamental Diagram of urban traffic. To verify the validity of this formulation, data from a micro-simulation of the City of Orlando, Florida, are used to derive an observed relationship with which to compare to theory. The simulated data are shown to match the theoretical predictions very well, and confirm the existence of hysteresis in the relationship between the mean and variance of travel times that is suggested by theory. These results can be used as a first step to more accurately represent travel time reliability in future models of traveler decision-making.",
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Relationship between mean and day-to-day variation in travel time in urban networks. / Gayah, Vikash Varun; Dixit, Vinayak V.; Guler, Sukran Ilgin.

In: EURO Journal on Transportation and Logistics, Vol. 3, No. 3-4, 01.10.2014, p. 227-243.

Research output: Contribution to journalArticle

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