a b s t r a c tThe present paper deals with timetable optimisation from the perspective of minimising the waiting time experienced by passengers when transferring either to or from a bus. Due to its inherent complexity, this bi-level minimisation problem is extremely difficult to solve mathematically, since timetable optimisation is a non-linear non-convex mixed integer problem, with passenger flows defined by the route choice model, whereas the route choice model is a non-linear non-continuous mapping of the timetable. Therefore, a heuristic solution approach is developed in this paper, based on the idea of varying and optimising the offset of the bus lines. Varying the offset for a bus line impacts the waiting time passengers experience at any transfer stop on the bus line.In the bi-level timetable optimisation problem, the lower level is a transit assignment calculation yielding passengers' route choice. This is used as weight when minimising waiting time by applying a Tabu Search algorithm to adapt the offset values for bus lines. The updated timetable then serves as input in the following transit assignment calculation. The process continues until convergence.The heuristic solution approach was applied on the large-scale public transport network in Denmark. The timetable optimisation approach yielded a yearly reduction in weighted waiting time equivalent to approximately 45 million Danish kroner (9 million USD).
Understanding the motivators of travel satisfaction is essential for designing attractive public transport systems. This study investigates the key drivers of satisfaction with public transport and their relationship with travel frequency and willingness to recommend public transport to others, hence contributing specifically by analysing the influence of social norms in travel use. A large-scale passenger satisfaction survey collected in six European cities and structural equation modelling validates the framework across different travel cultures. The study found that travel satisfaction is positively related to i) accessibility measures, e.g. extent of network coverage, travel speed and service frequency, ii) perceived costs, e.g. reasonable ticket prices, and iii) norms, i.e. perceived societal and environmental importance of public transport. These findings were consistent across all six cities and across different user types based on use frequency of public transport and private car. Specifically, the willingness to recommend public transport to others was significantly related to public transport use at a similar level as overall satisfaction. Finally, the study found significant differences in satisfaction across respondents' socio-economic characteristics as young respondents and students were less satisfied with service quality than middle-aged and elderly respondents despite more frequent use. This suggests structural problems in public transport because travel habits formed in early life shape travel behaviour throughout life. Hence, it is important to address the needs of these user groups to ensure public transport ridership in the future. The results bear important policy implications for planners in not only focusing on traditional measures for optimising operations, but also branding public transport as an environmentally and socially important transport mode in metropolitan areas.
Cities worldwide are implementing modern transit systems to improve mobility in the increasingly congested metropolitan areas. Despite much research on the effects of such systems, a comparison of effects across transit modes and countries has not been studied comprehensively. This paper fills this gap in the literature by reviewing and comparing the effects obtained by 86 transit systems around the world including Bus Rapid Transit (BRT), Light Rail Transit (LRT), metro, and heavy-rail transit systems. The analysis is twofold by analysing i) the direct operational effects related to travel time, ridership, and modal shifts, and ii) the indirect strategic effects in terms of effects on property values and urban development. The review confirms the existing literature suggesting that BRT can attract many passengers if travel time reductions are significantly high. This leads to attractive areas surrounding the transit line with increasing property values. Such effects are traditionally associated with attractive rail-based public transport systems. However, a statistical comparison of 41 systems did not show significant deviations between effects on property values resulting from BRT, LRT, and metro systems, respectively. Hence, this paper indicates that large strategic effects can be obtained by implementing BRT systems at a much lower cost.
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