Abstract

This paper analyzes the relation between commuting time and health in the United Kingdom. I focus on four different types of health outcomes: subjective health measures, objective health measures, health behavior, and health care utilization. Fixed effect models are estimated with British Household Panel Survey data. I find that whereas objective health and health behavior are barely affected by commuting time, subjective health measures are clearly lower for people who commute longer. A longer commuting time is, moreover, related to more visits to the general practitioner. Effects turn out to be more pronounced for women and for commuters driving a car. For women, commuting time is also negatively related to regular exercise and positively to calling in sick.

Abstract

Due to the geographical distance between producers and consumers, the impact of our current transport system on the environment is considerable. In an ideal, more sustainable transport system, several complementary transport modes are available, so that the most suitable route can always be selected. Because multiple transport modes and operators are involved, decision processes become more complex. That is why this research focuses on the development of innovative transport systems with realistic characteristics and planning limitations, in order to stimulate intermodal transport. Two planning tools have been developed to support decisions made by intermodal transport planners. It concerns on the one hand the integration of intermodal short and long distance routing and on the other hand the loading planning of trains. Both tools consist of fast planning algorithms that can handle realistic problem properties and can be integrated into transport management systems. The objective is to minimize transport costs and to make maximum use of available transport capacity.

Abstract

traffic control (ATC) simulator and on-the-job training requires a valid and reliable assessment system. Competence-based assessment results in more effective learning processes and better founded pass–fail decisions, which may contribute to an increased output of competent controllers from training. At Air Traffic Control The Netherlands (LVNL) we designed an assessment system based on a newly defined set of competences. The ATC Performance Model, derived from this competence analysis, has served as a framework for the design. This article describes the background, the design process, the properties, and the evaluation results of the competence-based assessment system in use by LVNL.

Abstract

Reducing traffic congestion via toll pricing has been a central topic in the operations research and transportation literature and, recently, it has been implemented in several cities all over the world. Since, in practice, it is not feasible to impose tolls on every edge of a given traffic network, we study the resulting mathematical problem of computing tolls on a predefined subset of edges of the network so as to minimize the total travel time of the induced equilibrium flow. We first present an analytical study for the special case of parallel edge networks highlighting the intrinsic complexity and nonconvexity of the resulting optimization problem. We then present algorithms for general networks for which we systematically test the solution quality for large-scale network instances. Finally, we discuss the related optimization problem of computing tolls subject to a cardinality constraint on the number of edges that have tolls. © 2015 Wiley Periodicals, Inc. NETWORKS, Vol. 653, 262-285 2015

Abstract

Inefficient transport systems impose extra travel time for travelers, cause dissatisfaction and reduce service levels. In this study, the demand-oriented train scheduling problem is addressed using a robust skip-stop method under uncertain arrival rates during peak hours. This paper presents alternative mathematical models, including a two-stage scenario-based stochastic programming model and two robust optimization models, to minimize the total travel time of passengers and their waiting time at stations. The modeling framework accounts for the design and implementation of robust skip-stop schedules with earliness and tardiness penalties. As a case study, each of the developed models is implemented on line No. 5 of the Tehran metro, and the results are compared. To validate the skip-stop schedules, the values of the stochastic solution and the expected value of perfect information are calculated. In addition, a sensitivity analysis is conducted to test the performance of the model under different scenarios. According to the obtained results, having perfect information can reduce up to 16% of the value of the weighted objective function. The proposed skip-stop method has been shown to save about 5% in total travel time and 49% in weighted objective function, which is a summation of travel times and waiting times as against regular all-stop service. The value of stochastic solutions is about 21% of the value of the weighted objective function, which shows that the stochastic model demonstrates better performance than the deterministic model. Document type: Article