Optimal stop spacing and headway of congested transit system considering realistic wait times

Abstract

This paper revisits the classical transit scheduling problem and investigates the relationship between stop spacing and headway, considering realistic wait time and operable transit capacity. Headway and stop spacing are important determinants for planning a transit system, which influence the service level as well as the cost of operation. A mathematical model is developed, and the objective function is user travel time which is minimized by the optimized stop spacing and headway, subject to the constraints of operable fleet size and route capacity. Optimal stop spacing and headway solutions are obtained in a numerical example. Sensitivity analysis is conducted, and the effect of model parameters on user travel time is explored.     

Does ISO 9000 series certification matter for the financial performance of ports? Some preliminary findings from Europe

This article investigates the role of ISO 9000 certification on the financial performance of the port authorities. The financial and scale efficiency of 18 European port authorities, some certified and some not, have been reviewed and results derived using data envelopment analysis. The inputs and outputs used in the analysis were selected following the literature and after employing regression analysis on the whole data set and the results reveal that ISO certified ports are more efficient financially than their non-certified competitors. By further using the efficiency slacks from the frontier, an indicative estimation of the magnitude of this inefficiency has been also calculated. The method followed may provide the impetus for a research agenda aiming explicitly on the exact contribution of certification on the financial ‘below the line’ results of the companies.     

Day-to-day variability in travellers’ activity-travel patterns in the Jakarta metropolitan area

Using four consecutive days of SITRAMP 2004 data from the Jakarta metropolitan area (JMA), Indonesia, this study examines the interactions between individuals’ activity-travel parameters, given the variability in their daily constraints, resources, land use and road network conditions. While there have been a significant number of studies into day-to-day variability in travel behaviour in developed countries, this issue is rarely examined in developing countries. The results show that some activity-travel parameter interactions are similar to those produced by travellers from developed countries, while others differ. Household and individual characteristics are the most significant variables influencing the interactions between activity-travel parameters. Different groups of travellers exhibit different trade-off mechanisms. Further analyses of the stability of activity-travel patterns across different days are also provided. Daily commuting time and regular work and study commitments heavily shape workers’ and students’ flexibility in arranging their travel time and out-of-home time budget, leading to more stable daily activity-travel patterns than non-workers.     

Testing the SERVQUAL scale in the passenger port industry: a confirmatory study

A key question is whether the service quality instruments developed for other services’ industries may be used to gauge service quality perceptions in shipping. Grounded on similar studies that test the most widely used American service quality instrument, SERVQUAL, in the commercial shipping sector, this study examines its applicability in the passenger shipping realm. Based on a survey of 436 passengers in Piraeus port, SERVQUAL's five main dimensions have been checked regarding their fit with the use of Confirmatory Factor Analysis. Results support that this is a valid instrument for measuring service quality in passenger shipping besides certain considerations regarding its dimensionality. A more parsimonious two-factor model seems more applicable and should therefore be also considered. Finally, it is evident from the study that passengers place more importance to the physical than the interactive elements of service to form their overall satisfaction.