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Dr. David M. Levinson

Persistent link for this collectionhttps://hdl.handle.net/11299/179806

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Browsing Dr. David M. Levinson by Author "Carrion, Carlos"

Now showing 1 - 6 of 6
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    A Model of Bridge Choice Across the Mississippi River in Minneapolis
    (Springer, 2011) Carrion, Carlos; Levinson, David
    On September 18th 2008, a replacement for the previously collapsed I-35W bridge opened to the public. Consequently, travelers were once again confronted with the opportunity to find better alternatives. The traffic pattern of the Minneapolis road network was likely to readjust, because of the new link addition. However, questions arise about the possible reasons (or components in the route choice process) that are likely to influence travelers crossing the Mississippi, who had to choose among the bridge options, including the new I-35W bridge. Using GPS data and web-based survey collected both before and after the replacement bridge opened, a bridge choice model is estimated using weighted-least squares logit. In this way the proportion of I-35W trips can be estimated depending on the assigned values of the explanatory variables, which include: statistical measures of the travel time distribution experienced by the subjects, alternative diversity, and others. The results showed that travel time savings and reliability were the main reasons for choosing the new I-35W bridge.
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    Monte Carlo Simulation of Adaptive Stated Preference Survey with a case study: Effects of Aggregate Mode Shares on Individual Mode Choice
    (2012) Carrion, Carlos; Tilahun, Nebiyou J; Levinson, David M
    Monte Carlo experiments are used to study the unbiasedness of several common random utility models for a proposed adaptive stated preference survey. This survey is used to study the influence of the knowledge of existing mode shares on travelers mode choice. Furthermore, the survey is applied to a sample of subjects selected from the University of Minnesota. The results indicate that the presence of mode shares in the mode choice model does influence the decision of travelers. The estimates are found to be biased by the Monte Carlo experiments.
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    Route choice dynamics after a link restoration
    (2012) Carrion, Carlos; Levinson, David M
    Carrion and Levinson (2012) studied the bridge choice behavior of commuters before and after a new bridge opened to the public. This bridge replaced the previously collapsed I-35W bridge in the metro area of Minneapolis-St. Paul. The original I-35W bridge collapsed on August 1st 2007, and the replacement bridge opened to the public on September 18th 2008. This study extends Carrion and Levinson (2012) by considering explicitly the day-to-day behavior of travelers, and by also considering the previously excluded subjects that are transitioning between bridge alternatives not including the I-35W bridge. The primary results indicate that the subjects react to day-to-day travel times on a specific route according to thresholds. These thresholds help discriminate whether a travel time is within an acceptable margin or not, and travelers may decide to abandon the chosen route depending on the frequency of travel times within acceptable margins. The secondary results indicate that subjects previous experience, and perception of the alternatives also influence their decision to abandon the chosen route.
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    Uncovering the influence of commuters' perception on the reliability ratio.
    (2012) Carrion, Carlos; Levinson, David M
    The dominant method for measuring values of travel time savings (VOT), and values of travel time reliability (VOR) is discrete choice modeling. Generally, the data sources for these models are: stated choice experiments, and revealed preference observations. There are few studies using revealed preference data. These studies have only used travel times measured by devices such as loop detectors, and thus the perception error of travelers has been largely ignored. In this study, the influence of commuters’ perception error is investigated on data collected of commuters recruited from previous research. The subjects’ self-reported travel times from surveys, and the subjects’ travel times measured by GPS devices were collected. The results indicate that the subjects reliability ratio is greater than 1 in the models with self-reported travel times. In contrast, subjects reliability ratio is smaller than 1 in the models with travel times as measured by GPS devices.
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    Valuation of Travel Time Reliability from a GPS-based Experimental Design
    (2013) Carrion, Carlos; Levinson, David M
    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.
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    Value of Travel Time Reliability: A review of current evidence.
    (Elsevier, 2012) Carrion, Carlos; Levinson, David M
    Travel time reliability is a fundamental factor in travel behavior. It represents the temporal uncertainty experienced by users in their movement between any two nodes in a network. The importance of the time reliability depends on the penalties incurred by the users. In road networks, travelers consider the existence of a trip travel time uncertainty in different choice situations (departure time, route, mode, and others). In this paper, a systematic review of the current state of research in travel time reliability, and more explicitly in the value of travel time reliability is presented. Moreover, a meta-analysis is performed in order to determine the reasons behind the discrepancy among the reliability estimates.