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Featured researches published by Karl Wunderlich.


Transportation Research Record | 2001

TIME MANAGEMENT IMPACTS OF PRETRIP ADVANCED TRAVELER INFORMATION SYSTEMS: FINDINGS FROM A WASHINGTON, D.C., CASE STUDY

Vaishali Shah; Karl Wunderlich; James Larkin

Numerous consumer surveys conclude that users of advanced traveler information systems (ATIS) perceive benefits foremost in travel time, followed by benefits of stress reduction and on-time arrival. Efforts by ATIS evaluators to quantify or empirically validate these benefits through field trials have yielded findings in travel time savings that are inconsistent with findings from surveys. It is hypothesized that users of ATIS benefit in the form of time management and not necessarily by reducing in-vehicle travel time. A novel approach (the simulated yoked study) is presented to evaluate the benefits to commuters from regular ATIS use. To demonstrate the simulated yoked study approach and to test the hypothesis, a case study based on travel conditions in Washington, D.C., between August 1, 1999, and October 1, 1999, was conducted. The travel experiences of commuters regularly using pretrip ATIS are simulated and compared with those of similar commuters using no traveler information before or during their commute. Findings from the case study indicate that benefits are significant in terms of on-time reliability but not in terms of the most frequently used measure of ATIS effectiveness, reduction of in-vehicle travel time. On average, regular pretrip ATIS users can reduce late arrivals by 69 percent and total late schedule delay by 72 percent compared with their counterparts. The regional reliability of the pretrip ATIS service, defined as the percentage of trips using pretrip ATIS that have arrival expectations that are met, is estimated at 77 percent. Analyses of pretrip ATIS user expectations, outcomes, and counterpart outcomes indicated that users’ perceptions of ATIS satisfaction are accurate.


SHRP 2 Report | 2013

Effectiveness of Different Approaches to Disseminating Traveler Information on Travel Time Reliability

Beverly Kuhn; Laura Higgins; Alicia Nelson; Melisa D Finley; Gerald L Ullman; Susan T Chrysler; Karl Wunderlich; Vaishali Shah; Conrad L Dudek

A key component to addressing the reliability issue related to urban mobility is conveying this reliability-related information to system users so that they can make informed decisions about their travel. The goal of the Strategic Highway Research Program 2 (SHRP 2) L14 project, Effectiveness of Different Approaches to Disseminating Traveler Information on Travel Time Reliability, is to examine what combination of words, numbers, and other features of user information messages, along with communications methods and technology platforms, best communicate information about travel time and reliability to travelers so they can make optimal travel choices from their point of view, such as whether to take a trip, departure time, mode choice, and route choice. This final report documents the research conducted as part the SHRP 2 L14 project. One of the main work products from the L14 project is the Lexicon for Conveying Travel Time Reliability Information, which offers recommendations to system operators on appropriate ways to provide travel time reliability information to travelers so that the information is most likely to be understood and used by travelers to influence their travel choices. The research team identified several key elements of a lexicon entry that were deemed necessary to completely present each term and how it might be used within the transportation community. One purpose of this final report is to describe the process that led to the development of the lexicon. The research began with a literature review to document existing practices and lessons learned regarding the communication of both travel and non-travel-related reliability information. The team then focused on conducting expert interviews and a technology and innovation scan to further examine the state of the practice in communicating information to travelers. The team also conducted a series of human factors experiments, including focus groups and surveys, to assess travelers’ comprehension and preferences for various reliability-related words and phrases. Finally, two laboratory experiments developed a utility function for travel time reliability information by observing participants’ use of reliability information during simulated commute trips and soliciting their opinions about the monetary value of that information. The lexicon was developed as the final task of this project.


Transportation Research Record | 2004

MAKING THE MOST OF LIMITED DATA IN EVALUATING ADVANCED TRAVELER INFORMATION SYSTEMS BY EXPERIMENTAL RESAMPLING

Meenakshy Vasudevan; Karl Wunderlich; Alan Toppen; James Larkin

Because of high data collection costs, analysts are commonly faced with the problem of limited data in the evaluation of intelligent transportation systems. How reliable are conclusions based on small samples? If limited data are available, how does one maximize their value? These questions were addressed to evaluate the potential benefits of prospective notification-based traveler information services used to deliver pre-trip travel time information to simulated drivers in a Cincinnati, Ohio, case study. In Cincinnati, travel time data were initially available for only 30 weekdays. An analysis that used this small data set indicated that an advanced traveler information system (ATIS) user would reduce disutility by 32% versus a comparable nonuser. However, since trip experiences on 30 weekdays may not characterize the typical experience of a commuter, conclusions drawn from the small sample may not accurately represent a more generalized assessment of the benefits of ATIS. Hence, an analogue of statistical resampling (experimental resampling) was applied to generate a large sample of days over which the effectiveness of ATIS could be evaluated. With experimental resampling, the reduction in disutility for an ATIS user was only 24%. It was concluded that experimental resampling provided a more reliable estimate of the benefit. To validate the claim, a more extensive study used 154 weekdays spanning a year. The validation analysis found that when compared with the small sample of 30 weekdays, the resampled cases were better predictors of the benefits for the large sample of 154 weekdays.


Transportation Research Record | 2003

Potential of advanced traveler information system to reduce travel disutility: Assessment in Washington, D.C., Region

Vaishali Shah; Karl Wunderlich; Alan Toppen; James Larkin

A study quantified the potential benefit of a pretrip advanced traveler information system (ATIS) to travelers in the Washington, D.C., region for the commuter objective of consistently on-time arrival. Paired driver commutes were simulated with a 15-month archive of regional travel times from Smar Traveler.com, an Internet provider of real-time data on travel time. One driver used a personalized pretrip notification service in selecting departure time and route, while the paired counterpart maintained a habitual trip departure time and route. The pairs’ trip arrivals were compared to quantify the effects on time management of a prospective notification service prescribing departure time and route. Approximately 25.9 million paired driver trials were modeled across a network of 55 nodes and 150 links, traversing 711.8 mi of roads in the Washington, D.C., metropolitan region. Trips were simulated for arrivals at 15-min intervals between 6:30 a.m. and 6:30 p.m. on workdays from each node to every other node. Overall, regular use of the pretrip ATIS is shown to benefit commuters whose objective is arriving on time. At low levels of ATIS market penetration, routine ATIS use could reduce early arrivals by 56% and late arrivals by 52%. Benefit in vehicle travel time is minimal. By applying a utility function to each trip, it was calculated that ATIS service reduces aggregate travel disutility by 15%. Approximately 67% of trips (origin–destination) derive a net benefit from routine ATIS use, while 40% benefit by more than


Transportation Research Record | 2007

Estimating User Costs and Economic Impacts of Roadway Construction in Six Federal Lands Projects

Matthew Hardy; James Larkin; Karl Wunderlich; A J Nedzesky

60/year. Benefits are fairly distributed across the year and are generally greatest during the evening peak.


Transportation Research Record | 2005

Comparison of Mobility Impacts on Urban Commuting: Broadcast Advisories Versus Advanced Traveler Information Services

Meenakshy Vasudevan; Karl Wunderlich; James Larkin; Alan Toppen

The Federal Lands Highway (FLH) Division staff faces myriad challenges when designing roadway construction projects for roads located on federal lands. An increasingly prevalent challenge is considering not only the “hard” costs of a construction project (e.g., labor and materials) but also the “soft” costs of user delay and the economic impacts on roadway users (e.g., residents, visitors, staff, and local businesses). These soft costs affect every roadway construction project but rarely are considered in design and operation because they often are difficult to estimate and justify. FHWAs 1998 report Meeting the Customers Needs for Mobility and Safety During Construction and Maintenance Operations identifies this issue and recommends that engineers begin to address it, for small- as well as large-scale projects. As part of its responsibility to promote the development and deployment of applied research, FLH staff initiated the development of FLH-QuickZone to help estimate these soft costs of roadway construction. As part of its development, FLH-QuickZone was tested and prototyped in six FLH construction projects: three in national parks, two on forest highways, and one in a national recreation area. Where FLH-QuickZone fits in a spectrum of other estimation tools for work zone delay and how it was used in the six FLH roadway construction projects are summarized. Observations about the challenge of addressing the soft cost of roadway construction projects–with FLH-QuickZone or other analytical tools–also are presented.


international conference on intelligent transportation systems | 2004

Rapid nationwide congestion monitoring: the urban congestion reporting program

Soojung Jung; Karl Wunderlich; James Larkin; Alan Toppen

This paper explores the effectiveness of relying on commercial radio as a source of traveler information and presents an approach to quantify mobility benefits from radio traffic advisories. The study, conducted for the Washington, D.C., metropolitan area, used an analytical technique called the heuristic online web-linked arrival time estimator to examine whether broadcast traffic advisories could have mobility benefits similar to a prospective notification-based traveler information service offering personalized estimates of travel times. Traffic reports were recorded from a local radio station and manually coded to translate them into a suitable format for analysis. Results from the analysis of 37 weekdays consisting of 4,410 advisories indicated that radio traffic advisories were less effective in improving traveler on-time reliability or reducing travel disutility than a service offering route-specific travel time reports. The simulated commuter receiving regular quantitative estimates of travel times on relevant roadways typically made more effective route and trip-timing decisions than the simulated commuter receiving comparatively incomplete, irregular, and vague advisories on prevailing congestion conditions from broadcast traffic reports. In contrast, the simulated commuter listening to radio advisories recorded similar benefits to those of the simulated control subject, who ignored all forms of traveler information. During the morning peak period, the simulated radio listener fared worse than the simulated control subject and recorded lower on-time reliability performance and higher travel disutility. During the afternoon peak period, the simulated radio listener had lower travel disutility but also experienced a nominal reduction in on-time reliability performance.


Transportation Research Record | 2004

Toward a strategy for cost-effective deployment of advanced traveler information systems

Alan Toppen; Soojung Jung; Vaishali Shah; Karl Wunderlich

In order to meet a federal request for monthly nationwide congestion monitoring and reporting capability, the Urban Congestion Reporting (UCR) program was developed - an effort that acquires and analyzes travel time data provided by advanced traveler information systems (ATIS) across the nation. Ten cities are now included in monthly reports that refine travel time data into three key regional congestion measures: hours of congested travel (temporal duration of congestion), travel time index (measuring the intensity of delay under congested conditions), and buffer index (a measure of day-to-day travel time variability). Data acquisition and analysis have been successfully automated to meet the FHWA goal of having draft monthly reports issued within 10 working days from the close of the month under analysis. This rapid analysis and reporting program has provided FHWA with a significant new capability to augment its established congestion monitoring program.


Transportation Research Record | 2007

Quantifying Reductions in Commute Disutility from Traveler Information Services

Meenakshy Vasudevan; Karl Wunderlich

The effects of advanced traveler information system (ATIS) accuracy and the extent of ATIS roadway instrumentation on the on-time reliability benefits to routine users of ATISs were evaluated by using archived estimates of roadway travel times to re-create hypothetical, retrospective paired driving trials between travelers with and without ATISs. Previous research using this technique demonstrated that travelers who received notification of congestion before departure could realize time management benefits from improved on-time reliability and trip predictability. On the basis of millions of hypothetical trips over a 12-month period in Los Angeles, California, it was found that a net benefit to an average user of ATIS existed if the error in travel time estimation was in the range of 14% to 21% or better, a threshold that depended on regional day-to-day travel time variability. For less accurate ATIS services, only certain subsets of the driving population, such as those with relatively long or highly variable trips, may realize any benefit. Furthermore, it was observed that a nearly optimal geographical deployment of ATIS could garner as much as 56% of the benefit of full coverage from the first 30% of deployment. Yet, the best deployment strategy is not as simple as prioritizing links on the basis of day-to-day variability. In making cost-effective trade-off decisions about how to invest in improved ATISs, be it expanding geographic coverage or improving accuracy, the findings underscore the importance of understanding the accuracy required to generate ATIS user benefits on the basis of regional day-to-day roadway variability.


Transportation Research Record | 2015

Predicting Congestion States from Basic Safety Messages by Using Big-Data Graph Analytics

Meenakshy Vasudevan; Daniel Negron; Matthew Feltz; Jennifer Mallette; Karl Wunderlich

An approach is presented for quantifying commute disutility measures. The approach was demonstrated through a case study conducted for the Washington, D.C., metropolitan area by using an analytical technique called the heuristic on-line web-linked arrival time estimation. “Commute disutility” was defined as having pretrip, en route, and posttrip components on the assumption that there is disutility associated with a commuters expectation of the trip before trip start, the en route trip experience, and the actual outcome of the trip. Three types of regular commuters were modeled: the nonuser who does not use any traveler information and two kinds of traveler information user–the radio listener who listens to commercial broadcast traffic advisories and the advanced traveler information service user who uses a notification-based service that provides route-specific travel time estimates. Analysis showed that compared to nonusers, traveler information users had lower commute disutility. They had fewer late arrivals at their destinations, and in fewer instances their trip expectation before trip start did not match their actual trip experience. They had fewer instances of feeling at intermediate waypoints along a trip that they were running behind schedule. They modified their trip start times or took alternate routes on more than 65% of the trips. This may have resulted in some disutility because of changes to the regular commute behavior, but they are more informed and therefore more confident of the potential trip outcome than is a nonuser.

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