Showing papers in "Journal of transportation and statistics in 2002"
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TL;DR: The character of accessibility as measuring the situation of a location in a region rather than its intrinsic qualities is emphasized throughout this paper, and several formulations are developed with several formulations.
Abstract: The character of accessibility as measuring the situation of a location in a region rather than its intrinsic qualities is emphasized throughout this paper. A brief characterization lays the basis for a sketch of data requirements, a specification of operational definitions, and a review of earlier findings. The idea of accessibility under competition is developed with several formulations, which are then compared through a synthetic example. Concluding comments suggest some guidelines and future directions.
82 citations
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TL;DR: The article finds that CORSIM, though imperfect, is effective with some restrictions in evaluating signal plans on urban networks.
Abstract: The process of validation is crucial for the use of computer simulation models in transportation policy, planning, and operations. This article lays out obstacles and issues involved in performing a validation. Described is a general process that emphasizes five essential ingredients for validation: context, data, uncertainty, feedback, and prediction. A test bed is used to generate specific and general questions as well as to give concrete form to answers and to methods used in providing them. The traffic simulation model CORSIM serves as the test bed; it is applied to assess signal timing plans on a street network of Chicago. The validation process applied in the test bed demonstrates how well CORSIM can reproduce field conditions, identifies flaws in the model, and shows how well CORSIM predicts performance under new (untried) signal conditions. The article finds that CORSIM, though imperfect, is effective with some restrictions in evaluating signal plans on urban networks.
55 citations
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TL;DR: In this paper, the economic impacts of highway relief routes on small and medium-size communities in Texas were examined and per capita sales in four different industry sectors were chosen as the indicators of impact.
Abstract: A relief route is a segment of a highway that moves traffic around the central business district of a city. Planners perceive it as a means of enhancing mobility and often associate regional economic progress with construction of bypasses. This paper examines the economic impacts of highway relief routes on small- and medium-size communities in Texas. Per capita sales in four different industry sectors were chosen as the indicators of impact. The models suggest that the bypassed cities suffered a loss in per capita sales in all four industrial sectors considered. The magnitude of the traffic volume diverted appeared to be greatest determinant of the impact. The overall impacts of the bypass were the most negative for gasoline service stations and the least for service industries. The impacts were less negative for cities that had high per capita traffic volumes. In addition, city demographics, regional trends, and proximity to a large city were estimated to have important impacts on the local economy. The industrial sectors considered for analysis represent only a portion of the total economy of the city. Therefore, negative impacts to these sectors do not necessarily mean that the economy as a whole suffers.
27 citations
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TL;DR: In this paper, the authors extended previous research that identified and quantified induced demand in terms of vehicle miles traveled, by considering what type of demand is induced and which activities are consequently reduced.
Abstract: Additional highway capacity gained by increasing travel speed affects the share of time an individual allocated to daily activities, such as commuting and time spent at work, shopping, or at home. Using the 1990 and 1995 Nationwide Personal Transportation surveys and Federal Highway Administration data, this paper extends previous research that identified and quantified induced demand in terms of vehicle miles traveled, by considering what type of demand is induced and which activities are consequently reduced. While total travel times did not significantly change between 1990 and 1995, there was a significant change in activity duration. Further, as a result of additional capacity, workers spent less time at home and doing other activities. Nonworkers, in contrast, traveled more and spent more time shopping and at home, but less time at other activities. This points out the differences in discretionary and nondiscretionary activities for workers and nonworkers. It also suggests increased highway capacity provides real gains for people, at least in the short term, because time, not vehicle miles traveled, is the deciding factor for which activities are undertaken and which are eliminated.
21 citations
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TL;DR: In this article, a nested logit model of activity scheduling behavior is proposed to predict a daily activity pattern for commuters, which suggests a two-stage decision process in which commuters first plan or identify the non-work activities that need to be undertaken during the day, and second, schedule these activities in relation to the work activity schedule.
Abstract: This paper presents a nested logit model of activity scheduling behavior that can be used to predict a daily activity pattern for commuters. The behavioral paradigm embodied in the model suggests a two-stage decision process in which commuters first plan or identify the nonwork activities that need to be undertaken during the day, and second, schedule these activities in relation to the work activity schedule. Three possible scheduling periods are considered in the model: before work, at work, and after work. Alternative nested logit model structures are estimated on the 1996 San Francisco Bay Area activity survey sample to identify a plausible and statistically acceptable structure. Numerical examples are presented to show how the model, when combined with a Monte Carlo simulation and simple heuristics, can be used to generate daily activity schedule for commuters.
19 citations
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TL;DR: In this article, a constrained robust method for estimating origin-destination (OD) split proportions, which are used to identify the trip table, for a network is presented, based on a recently developed statistical procedure known in the literature as the L2 error.
Abstract: This paper presents a constrained robust method for estimating origin-destination (OD) split proportions, which are used to identify the trip table, for a network. The proposed approach is based on a recently developed statistical procedure known in the literature as the L2 error. Subsequently, a closed form solution for calculating the asymptotic variance associated with the multivariate estimator is derived. Because the solution is closed form, the computation time is significantly reduced as compared with computer intensive standard error calculation methods, and therefore confidence intervals for the estimators in real time can be calculated. As a further extension, the OD estimation model incorporates confirmation factor analysis for imputing origin volume data when these data are systematically missing for particular ramps. The approach is demonstrated on a corridor in Houston, TX, that has been instrumented with ITS automatic vehicle identification readers.
14 citations
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TL;DR: It is shown that there are differences between traditional measures and differences in accessibility between socioeconomic groups with different travel patterns.
Abstract: This paper explores the development of accessibility measure based on daily travel patterns. In contrast to traditional zone-based measures, distance is calculated using a predefined travel matrix. The travel pattern for each zone is used as a weight in the accessibility measure. This path-based accessibility measure is implemented in a computer program that is closely coupled to a transport-oriented geographic information system. The measure is demonstrated in an application for two Swedish counties. This paper shows that there are differences between traditional measures and differences in accessibility between socioeconomic groups with different travel patterns.
9 citations
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TL;DR: This paper proposes the use of a number of nonparametric comparison methods for evaluating traffic flow forecasting techniques, free of any distributional assumptions and can be legitimately used on small datasets.
Abstract: This paper proposes the use of a number of nonparametric comparison methods for evaluating traffic flow forecasting techniques. The advantage to these methods is that they are free of any distributional assumptions and can be legitimately used on small datasets. To demonstrate the applicability of these tests, a number of models for the forecasting of traffic flows are developed. The one-step-ahead forecasts produced are then assessed using nonparametric methods. Consideration is given as to whether a method is universally good or good at reproducing a particular aspect of the original series. That choice will be dictated, to a degree, by the user’s purpose for assessing traffic flow.
6 citations
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TL;DR: In this article, the authors assessed the results of Kentucky's comprehensive reform of its transit system, including the impact on the quality of transit service for Medicaid eligible users with three sources of data - financial and other service data, a sample of Medicaid eligible residents, and the transit providers.
Abstract: The cost of providing nonemergency transportation to Medicaid and other transportation eligible people has escalated sharply in the United States In response, many states have reformed their human services transportation delivery systems This paper assesses the results of Kentucky's comprehensive reform of its transit system, including the impact on the quality of transit service for Medicaid eligible users With three sources of data - financial and other service data, a sample of Medicaid eligible residents, and a sample of the transit providers - the paper assesses the effectiveness of the new system The data show that patronage levels increased dramatically under the new process, while unit costs declined substantially Further, despite measures taken to increase efficiency, passengers still expressed satisfaction with the service These positive results are attributed to an improved structure of accountability The paper also contains implications for future reforms
4 citations
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TL;DR: This article developed a simple approach to estimate annual vehicle travel by visitors to individual states separately using local or national surveys for domestic visitors but federal surveys for foreign visitors, and applied it to Florida for the 15-year period from 1984 through 1998.
Abstract: This paper develops a simple approach to estimating annual vehicle travel by visitors to individual states. Domestic and foreign visitors are considered separately. The approach uses local or national surveys for domestic visitors but federal surveys for foreign visitors. The approach is applied to Florida for the 15-year period from 1984 through 1998. Visitors accounted for about 9.8% to 12.7% of all vehicle travel in the state during this period. Variations over the time result from changes in the number of visitors and their characteristics such as the length of stay and party size.
2 citations
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TL;DR: In this paper, an innovative method for estimating the value of time (VOT) for intercity travelers with aggregate mode choice and origin-destination distribution data is presented. But it is based on the assumption that the current trip and mode distributions in a regional corridor are close to a "user-optimum" state, where all tripmakers have nearly perfect information about the fares and schedules of all competing transportation modes and mostly employ the criterion of minimum total trip cost in their tripmaking decision.
Abstract: This paper presents an innovative method for estimating the value of time (VOT) for intercity travelers with aggregate mode choice and origin-destination distribution data. The proposed method employs a network structure to capture the temporal and spatial interrelations of daily intercity trips among competing transportation modes. It is grounded on the assumption that the current trip and mode distributions in a regional corridor are close to a "user-optimum" state, where all tripmakers have nearly perfect information about the fares and schedules of all competing transportation modes and mostly employ the criterion of minimum total trip cost in their tripmaking decision. One can thus compare the current market share of each transportation mode with the estimated results to identify the best for VOT distribution. To realistically capture the competing environment for intercity trip decisions, the proposed method has incorporated not only the system performance factors in the modeling structure, but has also formulated the VOT as a distribution rather than a constant value across all system users. With the data from the northwest-southeast corridor of Korea, it has been demonstrated that the proposed method has the potential to circumvent the need to estimate time value with disaggregate surveys.