Frede, Lennart ;
Müller-Hannemann, Matthias ;
Schnee, Mathias
Efficient On-Trip Timetable Information in the Presence of Delays
Abstract
The search for train connections in state-of-the-art commercial timetable information systems is based on a static schedule. Unfortunately, public transportation systems suffer from delays for various reasons.
Thus, dynamic changes of the planned schedule have to be taken into account. A system that has access to delay information of trains (and uses this information within search queries) can provide valid alternatives in case a train change breaks. Additionally, it can be used to actively guide passengers as these alternatives may be presented before the passenger is already stranded at a station due to a broken transfer.
In this work we present an approach which takes a stream of delay information and schedule changes on short notice (partial train cancellations, extra trains) into account. Primary delays of trains may cause a cascade of so-called secondary delays of other trains which have to wait according to certain waiting policies between connecting trains. We introduce the concept of a dependency graph to efficiently calculate and update all primary and secondary delays. This delay information is then incorporated into a time-expanded search graph which has to be updated dynamically.
These update operations are quite complex, but turn out to be not time-critical in a fully realistic scenario. We finally present a case study with data provided by Deutsche Bahn AG showing that this approach has been successfully integrated into our multi-criteria timetable information system MOTIS and can handle massive delay data streams instantly.
BibTeX - Entry
@InProceedings{frede_et_al:DSP:2008:1584,
author = {Lennart Frede and Matthias M{\"u}ller-Hannemann and Mathias Schnee},
title = {Efficient On-Trip Timetable Information in the Presence of Delays},
booktitle = {ATMOS 2008 - 8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems },
year = {2008},
editor = {Matteo Fischetti and Peter Widmayer},
publisher = {Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik, Germany},
address = {Dagstuhl, Germany},
URL = {http://drops.dagstuhl.de/opus/volltexte/2008/1584},
annote = {Keywords: Timetable information system, primary and secondary delays dependency graph, dynamic graph update},
}
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Keywords: |
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Timetable information system, primary and secondary delays dependency graph, dynamic graph update |
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Seminar: |
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8th Workshop on Algorithmic Approaches for Transportation Modeling, Optimization, and Systems (ATMOS'08)
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Issue date: |
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2008 |
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Date of publication: |
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24.09.2008 |
