A Robust Schedule for Montpellier’s Tramway Network

Ullrich, Oliver; Lückerath, Daniel; Speckenmeyer, Ewald

doi:10.11128/sne.25.tn.10271

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…As shown by Genç (2003), Ullrich et al (2012Ullrich et al ( , 2015, regularity can also be utilized as a measure of the resilience of a timetable against small inevitable disturbances: with an assumed basic interval of 10 min two lines sharing resources can be arranged in such a way that each vehicle has a 5 min clearance to its predecessor. Thus, any vehicle can accumulate a delay of over 4 min without propagating it to the succeeding tram.…”

Section: Timetable Generationmentioning

confidence: 99%

Do regular timetables help to reduce delays in tram networks? It depends!

2015

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In public transit planning, regularity of timetables is seen as an important means to improve capacity efficiency by assuring an even trip distribution, as well as to improve product attractiveness and appreciation. This paper focuses on examining whether a regular timetable can also help to reduce network delay, especially resulting from inevitable small disturbances. Following the formulation of a mathematical optimization approach, we propose a number of conditions a network has to fulfill for timetable regularity to have a delay reducing impact. A set of three network properties is identified, which consists of (a) the sharing of resources between tram lines, (b) a low variability of driving times, and (c) the non-redundancy of the network's central resources. To test the impact of these properties, a series of optimization and simulation experiments is conducted on models of the tram network of the cities of Cologne, Germany, and Montpellier, France. Small disturbances are introduced to the simulated operations to check whether the presence of all three properties is necessary for a network to benefit from a regular timetable. The results show that while with all properties present a regular timetable can indeed help to reduce delays resulting from small disturbances, the non-compliance with any one of the conditions nullifies the impact of regularity on the result.

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Section: Timetable Generationmentioning

confidence: 99%

Do regular timetables help to reduce delays in tram networks? It depends!

2015

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“…Optimization models to generate regular timetables are for example proposed by Genç [11], Bampas et al [1] and Ullrich et al [19][20][21]. Genç develops an integer linear programming formulation to generate periodic timetables with variable basic intervals, maximizing the minimum headway between consecutive departures at stops shared by multiple lines.…”

Section: R E L a T E D R E S E A R C Hmentioning

confidence: 99%

“…In the following the MILP first described by Genç [11] will be extended with the capability to incorporate planning requirements, following the approach described by Ullrich et al [19][20][21]. Therefore, the model by Genç, which up to now was only published in his German PhD thesis, will first be introduced in summary before the extensions for the incorporation of planning requirements are described.…”

Section: G E N E R a T I N G R E G U L A R T I M E T A B L E S A D H mentioning

confidence: 99%

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A disjunctive program formulation to generate regular public transit timetables adhering to prioritized planning requirements

et al. 2018

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Timetable regularity, that is, equability of headways, is an important measure for service quality in high frequency public transit systems, assuring an evenly distributed passenger load as well as improving product attractiveness. However, to be feasible during daily operation a timetable may also have to adhere to other planning requirements, such as departure time coordination with other service providers or deliberately short headways to reduce the passenger load of follow-up vehicles. In this article, a disjunctive program formulation combining aspects of two previous optimization models is proposed, to generate regular public transit timetables adhering to planning requirements. The modeled requirements not only allow for the consideration of feasibility constraints from daily operations, but also for the consideration of simultaneous departures for transfer connections, an objective traditionally opposed to regularity. To show its applicability the approach is applied to two models of artificial transit networks as well as to models of the public transit network of Cologne, Germany. The results show that the proposed formulation can be used to generate timetables for network instances of realistic size in acceptable time. For networks consisting of multiple connected components it is shown that a decomposition approach can significantly reduce run times. K E Y W O R D Sdisjunctive programming, mixed integer programming,

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“…The resulting software tools were applied to the KVB network of Cologne, Germany (see [23]), and the TAM Tramway network of Montpellier, France (see [25] The simulation engine was run on up to eight processors of the described type, under the parameter set described in section 5.1. Average runtime, speedup and marginal utility are shown in table 3 and figure 9.…”

Section: 2mentioning

confidence: 99%

Model-based Parallelization of Discrete Traffic Simulation Models

Ullrich¹,

Lückerath²,

Speckenmeyer³

2014

SNE

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To re-establish regular operations in a tram traffic network after a large disturbance, e.g. resulting from vehicle breakdown or station closure, the viability of several rescheduling and rerouting strategies has to be evaluated prior to their implementation. Here, a multi-modal traffic simulation system can help to enhance the decision quality. Such a system obviously faces tight time constraints, so simulation data has to be acquired fast.In this paper we propose a method for the parallel execution of discrete traffic simulation models, which would accelerate data generation in comparison to a sequential model. To assess this method's dynamic behavior in real-world applications, some experiments conducted on a software system modeling schedule based tram traffic are presented.After giving an introduction to the scope and aim, we show some background on the parallelization of discrete simulation models. The main part of the paper begins with the proposal of a method to parallelize the execution of simulation models with problem specific properties. Some estimations of the method's efficiency are shared, followed by several experiments to highlight its dynamic behavior in real-world applications. The paper ends with a short summary and some thoughts on further research.

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A Robust Schedule for Montpellier’s Tramway Network

Cited by 4 publications

References 9 publications

Do regular timetables help to reduce delays in tram networks? It depends!

Do regular timetables help to reduce delays in tram networks? It depends!

A disjunctive program formulation to generate regular public transit timetables adhering to prioritized planning requirements

Model-based Parallelization of Discrete Traffic Simulation Models

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