| 1. |
- Häll, Carl Henrik, 1978-, et al.
(författare)
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The Integrated Dial-a-Ride Problem
- 2009
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Ingår i: Public Transport. - Berlin / Heidelberg : Springer. - 1866-749X .- 1613-7159. ; 1:1, s. 39-54
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a formulation of the Integrated Dial-a-Ride (IDARP). This problem is to schedule dial-a-ride requests, where some part of each journey may be carried out by a fixed route service. The IDARP is a generalization of the Dial-a-Ride Problem. An arc-based formulation is proposed, and it is shown how the model can be made easier to solve by arc elimination, variable substitution and the introduction of subtour elimination constraints. Small instances of the IDARP can be solved using an exact solution method, and one such instance is studied. We also describe how input and output data can be created and visualized in a geographic information system.
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| 2. |
- Peterson, Anders, Docent, 1976-, et al.
(författare)
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Deliverable D 3.1: Analysis of the gap between daily timetable and operational traffic
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fr8Rail II/Work-Package 3 Real-time network management and improved methods for timetable planning addresses the problem to improve capacity and punctuality in the railway system by developing concepts and methods for tactical planning and operational traffic. In this report the state-of-the-art has been summarised.The aim of the project is to:Propose concepts and methods that improve the annual and short-term timetable planning.Demonstrate how the proposed timetable planning concepts improve the prerequisites for real-time network management.Develop methods and tools that can reduce inefficiencies in real time network management.An important aspect is to improve the coordination between yards/terminals and the line network, and between Infrastructure Manager, Yard Managers, and freight Rail Undertakings.We motivate our research by the current situation in Sweden, which is characterised by low on-time performance for freight trains, dense and heterogenous traffic on the major railway lines, and a rigid annual timetabling process, which is non-suitable for short-term changes. We believe that better tools for network planning and management on tactical and operational level can help to connect planning and operational processes.Aiming for improvements of the operational traffic, there is a need for systematic development of methods applied at several planning horizons, based on both simulation and optimization techniques. Close to operation fast methods are needed, for example, based on meta-heuristics.The maintenance planning process and improvement potential have been described. This is a new piece of the puzzle and it is important to close the gap between timetable planning and operational traffic. The different planning processes at the Infrastructure Manager, the Rail Undertakings and the Maintenance Contractors should be aligned.When developing new approaches for computational decision-support tools for real-time network management, it is important — but very challenging — to evaluate and benchmark with existing software tools. We also observe that the research stream on computational decision-support and algorithm development for railway traffic management has not yet been sufficiently merged with the corresponding research stream focusing on aspects of human computer interaction.
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| 3. |
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| 4. |
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| 5. |
- Häll, Carl Henrik, 1978-
(författare)
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A Framework for Evaluation and Design of an Integrated Public Transport System
- 2006
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Operators of public transport always try to make their service as attractive as possible, to as many persons as possible and in a so cost effective way as possible. One way to make the service more attractive, especially to elderly and disabled, is to offer door-to-door transportation. The cost for the local authorities to provide this service is very high and increases every year.To better serve the needs of the population and to reduce the cost for transportation of elderly and disabled, public transportation systems are evolving towards more flexible solutions. One such flexible solution is a demand responsive service integrated with a fixed route service, together giving a form of flexible public transport system. The demand responsive service can in such a system be used to carry passengers from their origin to a transfer location to the fixed route network, and/or from the fixed route network to their destination.This thesis concerns the development of a framework for evaluation and design of such an integrated public transport service. The framework includes a geographic information system, optimization tools and simulation tools. This framework describes how these tools can be used in combination to aid the operators in the planning process of an integrated service. The thesis also presents simulations made in order to find guidelines of how an integrated service should be designed. The guidelines are intended to help operators of public transport to implement integrated services and are found by evaluating the effects on availability, travel time, cost and other service indicators for variations in the design and structure of the service.In a planning system for an integrated public transport service, individual journeys must in some way be scheduled. For this reason the thesis also presents an exact optimization model of how journeys should be scheduled in this kind of service.
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| 6. |
- Häll, Carl Henrik, 1978-, et al.
(författare)
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A modeling system for simulation of dial-a-ride services
- 2012
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Ingår i: Public Transport. - Berlin / Heidelberg : Springer. - 1866-749X .- 1613-7159. ; 4:1, s. 17-37
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Tidskriftsartikel (refereegranskat)abstract
- We present a modeling system for simulation of dial-a-ride services. It can be used as a tool for understanding and study how different designs, and different ways to operate a dial-a-ride service, affect the performance and efficiency of the service. The system simulates the operation of a dynamic dial-a-ride service that operates with multiple fleets of vehicles with different capacities, schedules and depots. It can be used to investigate how the setting of service and cost parameters and the design of the service affect the total cost for the operator and level of service for the customer. We describe the different modules in the system and the possible uses of the system. A short simulation study is performed to exemplify how it can be used. In this study the effects of including costs for customer discomfort are evaluated.
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| 7. |
- Häll, Carl Henrik, 1978-, et al.
(författare)
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Adjustments of public transit operations planning process for the use of electric buses
- 2019
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Ingår i: Journal of Intelligent Transportation Systems / Taylor & Francis. - : Taylor & Francis. - 1547-2450 .- 1547-2442. ; 23:3, s. 216-230
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates and discusses how the introduction of electric buses (EB), both battery and plug-in hybrid EB, will and should change the operations planning of a public transit system. It is shown that some changes are required in the design of a transit route network, and in the timetabling and vehicle scheduling processes. Other changes are not required, but are advisable, using this opportunity upon the introduction of EB. The work covers the main characteristics of different types of EB with a short description, including the most popular charging technologies, and it presents the generally accepted transit operations planning process. Likewise, it describes and analytically formulates new challenges that arise when introducing EB. The outcome of the analyses shows that multiple new considerations must take place. It is also shown that the different charging techniques will influence the operations planning process in different ways and to a varying extent. With overnight, quick and continuous charging, the main challenges are in the network route design step, given the possibility of altering the existing network of routes, with efficient and optimal changes of the timetabling and vehicle scheduling components. An illustrative example, based on four bus lines in Norrköping, Sweden, is formulized and introduced using three problem instances of 48, 82, and 116 bus trips. The main results exhibit the minimum number of vehicles required using different scenarios of charging stations.
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| 8. |
- Häll, Carl Henrik, 1978-, et al.
(författare)
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Adjustments of Public Transit Operations Planning Process for the Use of Electric Buses
- 2017
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Ingår i: TRB Annual Meeting Online, 2017. - : Transportation Research Board.
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Konferensbidrag (refereegranskat)abstract
- This work investigates and discusses how the introduction of electric buses (EB), both battery and plug-in hybrid EB, will and should change the operations planning of a public transit system. It is shown that some changes are required in the design of a transit route network, and in the timetabling and vehicle scheduling processes. Other changes are not required, but are advisable, using this opportunity upon the introduction of EB. The work covers the main characteristics of different types of EB with a short description, including the most popular charging technologies, and it presents the generally accepted transit operations planning process. Likewise, it describes and analytically formulates new challenges that arise when introducing EB. The outcome of the analyses shows that multiple new considerations must take place. It is also shown that the different charging techniques will influence the operations planning process in different ways and to a varying extent. With overnight, quick and continuous charging, the main challenges are in the network route design step, given the possibility of altering the existing network of routes, with efficient and optimal changes of the timetabling and vehicle scheduling components.
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| 9. |
- Häll, Carl Henrik, 1978-, et al.
(författare)
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Effects of distance estimation methods in dial-a-ride planning
- 2008
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Ingår i: Proceedings of the 13th International Conference of Hong Kong Society for Transportation Studies. - Hong Kong, China : Hong Kong Society for Transportation Studies (HKSTS). - 9789889884734 ; , s. 751-759
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 10. |
- Häll, Carl Henrik, 1978-, et al.
(författare)
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Evaluating the performance of a dial-a-ride service using simulation
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we study the effects of changes to a paratransit system operated as a dynamic dial-a-ride service. The scheduling of requests is limited by time window constraints and maximum ride time constraints, and costs for customer discomfort in form of waiting time and excess ride time, are considered in the planning of the service. The parameters defining these constraints and costs are evaluated based on simulations of a real-world scenario.Several different criteria, both regarding customer level of service and operational costs, are used to evaluate the simulation results. By showing what parameters that have a large impact on the different evaluation criteria, we can give guidelines to operators of public transport of how to design their dial-a-ride services. Numerical results are presented and from these results conclusions are drawn regarding what parameters are most important in dynamic dial-a-ride services.
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