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Effects of distance estimation methods in dial-a-ride planning
Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
Astando AB, 11221 Stockholm, Sweden.
2008 (English)In: Proceedings of the 13thInternational Conference of Hong Kong Society for Transportation Studies,Transportation and Management Science / [ed] Lo, H.P., C.H. Leung and S.M.L Tam, Hong Kong, China: Hong Kong Society of Transportation Studies Ltd. , 2008, 751-759 p.Conference paper (Refereed)
Abstract [en]

Paratransit in form of dial-a-ride service is widely used in Sweden. A main planning system in Sweden uses pre-calculated distance matrices, based on aggregated geographical zones. A trip between two zones is thereby assumed to take a certain time independent of where in the zones the actual pick-up and drop-off points are located. The aim of this paper is to examine the effects of using address-based shortest path calculations instead of zone-based distance estimates. A simulation environment is implemented in C#.Net, based on a standard formulation of the dynamic dial-a-ride problem, and simulations have been performed on historical data from the city of Göteborg. To evaluate the solutions, it is not adequate to evaluate only the objective function value, since a lower estimation of the distances will likely give a lower objective function value. Therefore we also discuss how to evaluate different solutions in other terms than objective function values.

Place, publisher, year, edition, pages
Hong Kong, China: Hong Kong Society of Transportation Studies Ltd. , 2008. 751-759 p.
Keyword [en]
transportation, planning, dial-a-ride
National Category
Engineering and Technology
URN: urn:nbn:se:liu:diva-43892Local ID: 75043ISBN: 978-988-98847-3-4OAI: diva2:264753
The 13th International Conference of Hong Kong Society for Transportation Studies, 13-15 December, Hong Kong, China
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2011-05-11Bibliographically approved
In thesis
1. Modeling and Simulation of Dial-a-Ride and Integrated Public Transport Services
Open this publication in new window or tab >>Modeling and Simulation of Dial-a-Ride and Integrated Public Transport Services
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Traditional public transport systems are most often insufficient to provide a good transport service to everyone. Especially, it is not always possible for elderly and disabled persons to use the regular system consisting of timetabled services operating along fixed routes. Normally there is some specific service, often called paratransit, offered to these groups of customers. Such transport services provide better service to these customers, but to a higher cost. This thesis considers planning and evaluation of public transport services that are based on the concept of a dial-a-ride service. This kind of service is suitable for elderly and disabled and often operated as a door-to-door service, where customers are served on demand and rides are coordinated via a call-center. The thesis is divided into two parts. In the first part, a modeling system for simulation of dial-a-ride services is presented. It can be used as a tool to study how different ways of operating a dial-a-ride service, affect the performance and efficiency of the service. This system is used to evaluate how algorithmic changes, based on ruin-and-recreate methods, can improve the replanning of already inserted requests, and thereby improve the scheduling. The modeling system is also used to examine the effects of using zone-based distance estimates instead of true, address-based, distances when computing the schedules. The results show that only small differences are found.The second part of the thesis concerns an extension to dial-a-ride services. By combining a dial-a-ride service with a fixed route service, an integrated dial-a-ride service is created, where some part of each journey may be carried out by the fixed route service. An exact mathematical formulation of this problem is presented and it is shown that the formulation is strengthened by valid inequalities, variable substitution and subtour elimination constraints. Simulations of an integrated service are also performed to analyze and evaluate how the attractiveness and operating costs of the service depend on how the demand responsive service is operated.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2011. 44 p.
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1379
dial-a-ride, simulation, optimization, modeling, paratransit, public transport
National Category
Other Engineering and Technologies not elsewhere specified
urn:nbn:se:liu:diva-68067 (URN)978-91-7393-135-9 (ISBN)
Public defence
2011-06-10, K3, Kåkenhus, Campus Norrköping, Linköpings universitet, Norrköping, 13:15 (English)
Available from: 2011-05-11 Created: 2011-05-10 Last updated: 2013-06-12Bibliographically approved

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Häll, Carl Henrik
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