| 1. |
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| 2. |
- Avery, Ryan, et al.
(författare)
-
An Interactive Tool for Collecting Traveler Behavior Information
- 2008
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Ingår i: Proceedings of the 87th Transportation Research Board Annual Meeting, Jan. 2008.
-
Konferensbidrag (refereegranskat)abstract
- Understanding driver behavior and response to traffic information is necessary in order toachieve the maximum benefit from Advanced Traveler Information Systems (ATIS). This paperdescribes the development of a travel simulator to collect information on driver route choice inresponse to traffic information. A main feature of the simulator is the realistic representation ofmultiple traffic information sources (currently VMS and radio messages). Furthermore, thesimulator is one of the first Internet-based travel simulators, and the only one that accuratelysimulated the driving task. The simulator consists of collection of pre-trip information anddefault route information followed by multiple simulated trips with varying incidents and trafficinformation. The simulator is evaluated and measures well against established guidelines fortravel simulator development. Results will be discussed in future papers as data collection usingthe simulator is ongoing as of August 2007.
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| 3. |
- Babicheva, Tatiana, et al.
(författare)
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Empty vehicle redistribution and fleet size in autonomous taxi systems
- 2019
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Ingår i: IET Intelligent Transport Systems. - : INST ENGINEERING TECHNOLOGY-IET. - 1751-956X .- 1751-9578. ; 13:4, s. 677-682
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigates empty vehicle redistribution algorithms for personal rapid transit and autonomous taxi services. The focus is on passenger service and operator cost. A new redistribution algorithm is presented in this study: index-based redistribution (IBR). IBR is a proactive method, meaning it takes into account both current demand and anticipated future demand, in contrast to reactive methods, which act based on current demand only. From information on currently waiting for passengers, predicted near-future demand and projected arrival of vehicles, IBR calculates an index for each vehicle station, and redistribution is done based on this index. Seven different algorithm combinations are evaluated using a test case in Paris Saclay, France (20 stations and 100 vehicles). A combination of simple nearest neighbours and IBR is shown to be promising. Its results outperform the other methods tested in peak and off-peak demand, in terms of average and maximum passenger waiting times as well as station queue length. The effect of vehicle fleet size on generalised cost is analysed. Waiting times, mileage and fleet size are taken into account while assessing this generalised cost.
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| 4. |
- Babicheva, Tatiana, et al.
(författare)
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Empty vehicle redistribution in autonomous taxi services
- 2019
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Ingår i: EURO Journal on Transportation and Logistics. - : SPRINGER HEIDELBERG. - 2192-4376 .- 2192-4384. ; 8:5, s. 745-767
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, we investigate empty vehicle redistribution algorithms for Personal Rapid Transit (PRT) or autonomous station-based taxi services, from a passenger service perspective. We present a new index-based redistribution (IBR) algorithm that improves upon existing nearest neighbour and indexing algorithms by incorporating expected passenger arrivals and predicted waiting times into the surplus/deficit index. We evaluate six variations of algorithms on a test case in Paris Saclay, France. The results show that especially the combination of Simple Nearest Neighbours + Index Based Redistribution provides promising results for both off-peak and rush-hour demand, outperforming the other methods tested, in terms of passenger waiting time (average and maximum) as well as station queue lengths.
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| 5. |
- Babicheva, T., et al.
(författare)
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The matching problem of empty vehicle redistribution in autonomous taxi systems
- 2018
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Ingår i: The 9th International Conference on Ambient Systems, Networks and Technologies (ANT 2018) / The 8th International Conference on Sustainable Energy Information Technology (SEIT-2018) / Affiliated Workshops. - : Elsevier. ; , s. 119-125
-
Konferensbidrag (refereegranskat)abstract
- This article discusses empty vehicle redistribution algorithms for PRT and autonomous taxi services from a passenger service perspective. In modern literature reactive methods such as nearest neighbours are commonly used. In this article we first formulate the general matching problem on a bipartite graph of available vehicles and stations. In addition, we propose a new index-based proactive redistribution (IBR) algorithm based on predicted near-future demand at stations. Test results of six variations of combined proactive and reactive strategies on a test case in Saclay, France with 20 stations and 100 vehicles are given. The combined Nearest Neighbour / IBR provides a promising solution for both peak and off-peak demand, significantly outperforming all other methods considered, in terms of passenger waiting time (both average and maximum) as well as in terms of station queue lengths.
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| 6. |
- Berg Wincent, Boel, et al.
(författare)
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Access distance to e-scooters : Analysis of app use and trip data in Stockholm
- 2023
-
Ingår i: Journal of Cycling and Micromobility Research. - : Elsevier. - 2950-1059. ; , s. 100004-100004
-
Tidskriftsartikel (refereegranskat)abstract
- Users’ access distance to shared micromobility services is an important component of travel patterns, a determinant of travel choices, and input to determining service catchment areas. Users’ willingness to walk to shared micromobility vehicles is increasingly relevant as policymakers regulate shared free-floating e-scooters to designated parking zones. This paper proposes a novel approach to analyze access distances of e-scooters users based on e-scooter app use and trip data for Stockholm, Sweden. Euclidean access and map-based walking distances are derived from the distances between the location where the users opens the app to search for an e-scooter and the trip’s origin. Variations in access and walking distances are analyzed based on time of day, day of week, proximity to public transportation, and geographical distribution. Users walk on average 185 m and have an active walking time of 2.3 min with a median value of 95 m and 2.1 min. Shorter walking distances are observed for trips during the morning and lunch hours compared to the afternoon and at night. Furthermore, users walk slightly longer during the weekend compared to weekdays. Access distances are shortest within a 0–100 m radius to the nearest public transportation station. The suggested catchment area radius for shared e-scooters ranges from 128 m to 203 m, based on the 75th percentile of access distances. A policy implication is the importance of planning parking zones for e-scooters very close to public transportation to encourage multimodal trips.
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| 7. |
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| 8. |
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| 9. |
- Berg Wincent, Boel, et al.
(författare)
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Parkering av elsparkcyklar : Enkätundersökning av effekter och åsikter kring parkeringsförbudet i Stockholm, Göteborg och Malmö
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Den 1 september 2022 infördes ett nationellt parkeringsförbud för elsparkcyklar i Sverige. Parkeringsförbudet innebar att delade elsparkcyklar enbart fick parkeras på särskilda platser för elsparkcyklar eller på cykelparkeringar. Stockholms stad och Malmö stad valde två olika utformningar av parkeringssystem för elsparkcyklar medan Göteborgs stad valde att skjuta upp införandet med hjälp av lokala trafikföreskrifter. Den här enkätstudien undersöker effekter och åsikter kring parkeringsförbudet hos delade elsparkcykelanvändare i Stockholm, Göteborg och Malmö. Syftet med enkätundersökningen är att förstå vad användarna har för önskemål och attityder relaterat till parkering av elsparkcyklar.Enkäten togs fram under hösten 2022 och skickades ut till elsparkcykeloperatören Vois användare i Stockholm, Malmö och Göteborg den 17 november 2022. Totalt inkom 1584 svar. 965 användare från Stockholm, 145 användare från Göteborg och 159 användare från Malmö ingick i det slutliga urvalet som låg till grund för resultatet. Majoriteten av användarna från alla tre städer var heltidsanställda, boende inom Vois driftzon, hade minst en eftergymnasial utbildning och var av manligt kön. Ålder och årsinkomst varierade något mellan städerna. Användare i Stockholm hade i genomsnitt använt 2,7 elsparkcykeloperatörer senaste sex månaderna medan användare i Göteborg hade använt 2,6 och i Malmö 2,2. I Stockholm och Göteborg var den vanligaste användarfrekvensen en eller flera gånger per vecka medan det i Malmö var en eller flera gånger per månad.Användarna i Stockholm och Malmö uppgav att deras användarfrekvens, gångtid och åktid för resor med elsparkcyklar hade påverkats efter 1 september. Användarna i Göteborg rapporterade i lägre utsträckning att deras användning hade påverkats efter 1 september 2022. Mest positiva till parkeringsförbudet var användarna i Stockholm medan användarna i Malmö var mest negativt inställda. Användarna upplevde att införandet av parkeringsförbudet inneburit mer ordning och reda i stadsmiljön men att tillgången till elsparkcyklar och möjligheten att parkera nära destination hade blivit sämre. Täthet och placering av parkeringszonerna för elsparkcyklar var de aspekterna som användarna i Stockholm och Malmö var mest missnöjda med samtidigt som det var de aspekterna som användarna i Göteborg ansåg som viktigast.Utöver täthet och placering frågades även användarna om storlek, tydlighet och enkelhet i parkeringssystemet samt hur operatörens app användes för att hitta parkering. Genomgående var användarna i Stockholm mindre missnöjda med utformningen av parkeringssystemet i jämförelse med användarna i Malmö. Det tolkas som att Stockholms stad har lyckats bättre med elsparkcykelparkering ur ett användarperspektiv. Fler än hälften av användarna i alla tre städer hade gjort en kombinerad resa med elsparkcykel och kollektivtrafik. Användarna i Malmö hade i högst utsträckning gjort multimodala resor med elsparkcykel och kollektivtrafik, men uppgav i lägst utsträckning att det var lätt att parkera vid en hållplats eller station. Möjligheten att parkera vid kollektivtrafik är viktigt att beakta om uppmuntran till multimodala resor med elsparkcyklar och kollektivtrafik är av prioritet.
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| 10. |
- Berg Wincent, Boel
(författare)
-
Shared e-scooter usage patterns : Analysis of app and trip data
- 2024
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is an urgent need to shift the urban mode distribution towards public transportation, micromobility, and shared mobility as a critical step towards achieving sustainable cities. Micromobility, with shared e-scooters as the main driving force, has sprung up as a promising mode for cities since the late 2010s. The development has been rapid and concurrent, with many changes in policy and operations. Given the novelty of the mode, there is an evident need for planners, policymakers, e-scooter companies, and researchers to understand the usage patterns and potentials of shared e-scooters. This thesis studied shared e-scooter usage patterns by analyzing app and trip data. Paper I analyses the access and walking distance to shared e-scooters. The Euclidean access distance was calculated from app and trip data. A process was then developed to estimate map-based walking distance from the Euclidean distance by removing and replacing outliers with an approximated value. Finally, a catchment area for shared e-scooters was presented. The result show that the walking distance is short, the majority walking less than 95 m and 2.1 min.Paper II evaluated shared e-scooters as a last-minute mode, a mode used as a way to mitigate the risk of late arrival. The study was based on the assumption of a preferred arrival time, which was tested where there was an associated risk of arriving late and when the assumed preferred arrival time shifts. Trip characteristics(speeds, distances, ride times, and trip frequency) of last-minute trips were analyzed and identified. The result show a peak in the number of trips ending before the full hour of the morning. These trips are infrequent on the user level and have lower average ride duration and higher average speeds, indicating an larger share of last-minute trips.
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| 11. |
- Berg Wincent, Boel, et al.
(författare)
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Shared e-scooters : A last-minute mode?
- 2024
-
Ingår i: Travel Behaviour & Society. - : Elsevier BV. - 2214-367X .- 2214-3688. ; 37
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we assess whether shared e-scooters are being used in hurried situations to avoid arriving late, making trips we define as last-minute trips. We identify trip characteristics for last-minute trips using data from shared e-scooters in Stockholm. Trip arrival time patterns, distances, durations, and speeds are analyzed in relation to desired arrival times. We observe a peak in the number of trips ending before the full hour and a smaller peak of trips ending before the half hour of weekday mornings. These trips have lower average trip durations and higher average speeds, indicating a larger share of last-minute trips. Arrival patterns shift when the assumed preferred arrival time changes, and when the risk associated with arriving late increases. Furthermore, there is an increased share of trips that started close to public transportation around the full hour, indicating that a portion of last-minute trips may also be last-mile trips. Our results show that while last-minute trips are infrequent per user, they do make up a relatively large share of weekday morning trips. These results highlight an important market segment for shared e-scooter services and may also explain why some research reports e-scooter usage replacing walking.
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| 12. |
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| 13. |
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| 14. |
- Berrada, Jaafar, et al.
(författare)
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Demand modelling of autonomous shared taxis mixed with scheduled transit
- 2019
-
Ingår i: Proceedings of the 98th Transportation Research Board (TRB) Annual Meeting.
-
Konferensbidrag (refereegranskat)abstract
- Autonomous taxis (aTaxis) are promising to restructure the urban mobility universe: dispatching vehicles on roads to minimize congestion, reducing accidents and thus increasing savings of travel time, improving the transit level of service and reducing operating costs of public modes, thus limiting public subsidies. The simulation of demand and supply for on-demand services while considering the interaction with other modes has not yet been sufficiently investigated.This paper proposes a framework for simulating on-demand aTaxi services, while considering interactions with scheduled transit. In particular, it is coupling an agent-based aTaxi model (VIPSIM) and the four-step model of VISUM. The framework is applied to a network in the Paris metropolitan area where aTaxis are implemented to replace a BRT service. Transfers between aTaxis and BRT are considered and a combined utility for public modes is calculated. The convergence between the two models is then performed. Results of the application case show that aTaxis improve the mobility performances of public transit. A supply management analysis proved that 20 aTaxis provides high service efficiency and increase the service profitability. Using 10 more vehicles attracts 15 more passengers. With 65 aTaxis, the demand is 10% higher with the same profit as the BRT.
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| 15. |
- Burghout, Wilco, et al.
(författare)
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A Discrete-Event Mesoscopic Traffic Simulation Model for Hybrid Traffic Simulation
- 2006
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Ingår i: IEEE Intelligent Transportation Systems Conference, 2006. ITSC'06. - : IEEE. - 1424400937 ; , s. 1102-1107
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Konferensbidrag (refereegranskat)abstract
- The paper presents a mesoscopic traffic simulation model, particularly suited for the development of integrated meso-micro traffic simulation models. The model combines a number of the recent advances in simulation modeling, such as discrete-event time resolution and combined queue-server and speed-density modeling, with a number of new features such as the ability to integrate with microscopic models to create hybrid traffic simulation. The ability to integrate with microscopic models extends the area of use to include evaluation of ITS systems, which often require the detailed modeling of vehicles in areas of interest, combined with a more general modeling of large surrounding areas to capture network effects of local phenomena. The paper discusses the structure of the model, presents a framework for integration with micro models, and illustrates its validity through a case study with a congested network north of Stockholm. It also compares its performance with a hybrid model applied to the same network.
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| 16. |
- Burghout, Wilco, et al.
(författare)
-
DYMOBUS: dynamic mesoscopic modelling of bus public transport
- 2009
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Ingår i: Conference proceedings to ITS 2009 conference.
-
Konferensbidrag (refereegranskat)abstract
- In today’s public bus transport punctuality is one of the main problems to deal with for traffic planners and operators, especially in large cities such as Stockholm. The current static models do not handle congestion delays and the interaction between bus and car traffic, leading to overly optimistic timetables and hard to manage delays. In the DYMOBUS project (Funded by VINNOVA and City of Stockholm) a dynamic modelling tool was developed in order to study these interactions. This paper discusses a mesoscopic, mixed-traffic, a transit simulation model designed to support evaluation of operations planning and control, especially in the context of Advanced Public Transportation Systems (APTS). Examples of applications include frequency determination, evaluation of real time control strategies for schedule maintenance and restoration from major disruptions. The transit simulation component is designed to represent realistically the uncertainty in operations, in order to assess service reliability. The simulation models all sources of uncertainty: chaining of trips, travel time variability, behavior at stops and a detailed representation of passenger demand at the various stops. Unlike most previous efforts in this area, the simulation model is built on the platform of a mesoscopic traffic simulation model, which allows modeling of the operations of large-scale transit systems. A Tel-Aviv case study demonstrates the transit simulation capabilities of the model.
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| 17. |
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| 18. |
- Burghout, Wilco, et al.
(författare)
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Hybrid Mesoscopic-Microscopic Traffic Simulation
- 2005
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Ingår i: Transportation Research Record. - 0361-1981 .- 2169-4052. ; 1934, s. 218-225
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Tidskriftsartikel (refereegranskat)abstract
- Traffic simulation is an important tool for modeling the operations of dynamic traffic systems. Although microscopic simulation models provide a detailed representation of the traffic process, macroscopic and mesoscopic models capture the traffic dynamics of large networks in less detail but without the problems of application and calibration of microscopic models. This paper presents a hybrid mesoscopic-microscopic model that applies microscopic simulation to areas of specific interest while simulating a large surrounding network in less detail with a mesoscopic model. The requirements that are important for a hybrid model to be consistent across the models at different levels of detail are identified. These requirements vary from the network and route choice consistency to the consistency of the traffic dynamics at the boundaries of the microscopic and mesoscopic submodels. An integration framework that satisfies these requirements is proposed. A prototype hybrid model is used to demonstrate the application of the integration framework and the solution of the various integration issues. The hybrid model integrates MlTSIMLab, a microscopic traffic simulation model, and Mezzo, a newly developed mesoscopic model. The hybrid model is applied in two case studies. The results are promising and support both the proposed architecture and the importance of integrating microscopic and mesoscopic models.
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| 19. |
- Burghout, Wilco, 1975-
(författare)
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Hybrid microscopic-mesoscopic traffic simulation
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traffic simulation is an important tool for modelling the operations of dynamic traffic systems and helps analyse the causes and potential solutions of traffic problems such as congestion and traffic safety. Microscopic simulation models provide a detailed representation of the traffic process, which makes them most suitable for evaluation of complicated traffic facilities and Intelligent Transportation Systems that often consist of complex traffic management, safety and information systems. Macroscopic and mesoscopic models on the other hand, capture traffic dynamics in lesser detail, but are faster and easier to apply and calibrate than microscopic models. Therefore they are most suitable for modelling large networks, while microscopic models are usually applied to smaller areas. The objective of this thesis is to combine the strengths of both modelling approaches and diminish their individual weaknesses by constructing a hybrid mesoscopic-microscopic model that applies microscopic simulation to areas of specific interest, while simulating a surrounding network in lesser detail with a mesoscopic model. Earlier attempts at hybrid modelling have concentrated on integrating macroscopic and microscopic models and have proved difficult due to the large difference between the continuous-flow representation of traffic in macroscopic models and the detailed vehicle-and driver-behaviour represented in microscopic models. These problems are solved in this thesis by developing a mesoscopic vehicle-based and event-based model that avoids the (dis)aggregation problems of traffic flows at the inter-model boundaries. In addition, this thesis focuses on the general problems of consistency across the entire hybrid model. The requirements are identified that are important for a hybrid model to be consistent across the models at different levels of detail. These requirements vary from network and route-choice consistency to consistency of traffic dynamics across the boundaries of the micro- and mesoscopic submodels. An integration framework is proposed that satisfies these requirements. This integration framework has been implemented in a prototype hybrid model, MiMe, which is used to demonstrate the correctness of the solutions to the various integration issues. The hybrid model integrates MITSIMLab, a microscopic traffic simulation model, and Mezzo, the newly developed mesoscopic model. Both the hybrid model and the new Mezzo model are applied in a number of case studies, including a network in the North of Stockholm, which show their validity and applicability. The results are promising and support both the proposed integration architecture and the importance of integrating microscopic and mesoscopic models.
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| 20. |
- Burghout, Wilco, et al.
(författare)
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Hybrid Traffic Simulation Models : Vehicle loading at meso-micro boundaries
- 2019
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Ingår i: Transport Simulation. - : CRC Press. - 9781420095098 - 9781439808016 ; , s. 27-42
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Traffic simulation models, especially microscopic ones, are becoming increasingly popular and are being used to address a wide range of problems, from planning to operations. However, for applications with large-scale networks, microscopic models are impractical because of input data and calibration requirements. Hybrid models that combine simulation models at different levels of detail have the potential to address these practical issues. This chapter presents a framework for implementing meso-micro hybrid models which facilitates a consistent representation of traffic dynamics. Furthermore, the chapter carries out a detailed examination of an important element impacting the consistent representation of traffic dynamics, i.e., the loading of vehicles from the meso- to the micro-model. A new loading method is presented demonstrating a superior performance as compared to existing approaches. The method is useful not only in the context of hybrid models, but also for microscopic models on their own. A case study illustrates the importance of the method in improving the fidelity of both hybrid and pure microscopic models.
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| 21. |
- Burghout, Wilco, et al.
(författare)
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Hybrid traffic simulation with adaptive signal control
- 2007
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Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; :1999, s. 191-197
-
Tidskriftsartikel (refereegranskat)abstract
- A hybrid mesoscopic-microscopic model is implemented that applies microscopic simulation to areas of specific interest while simulating a large surrounding network in lesser detail with a mesoscopic model. The hybrid model integrates VisSim, a microscopic traffic simulation model, and Mezzo, a recently developed mesoscopic model. The hybrid model is applied on a network in which Mezzo simulates the entire area (6,000 links) of Stockholm, Sweden, and VisSim simulates the area of specific interest, containing three intersections with adaptive signal control with bus-priority functions. The adaptive signal control and bus-priority functions are simulated by a separate signal controller simulator (EC-1 simulator) that interacts with the hybrid Mezzo-VisSim model and thereby provides the actual signal changes that would take place in the field. Two alternative control schemes are evaluated with the hybrid setup: the original fixed-time control and the new adaptive control. The results show clear improvement in terms of travel times, delays, and stops with the new adaptive control scheme. They also show that although these improvements for the local (microlevel) area attract additional traffic from the surrounding (mesolevel) area, the net effects both locally and networkwide remain positive in terms of travel times, average number of stops, and delay. Moreover, this study demonstrates the advantages of hybrid simulation in evaluation of complicated adaptive traffic control in which both local detailed effects and network effects need to be studied.
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| 22. |
- Burghout, Wilco, 1974-, et al.
(författare)
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Impacts of Shared Autonomous Taxis in a Metropolitan Area
- 2015
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Ingår i: Proceedings of the 94th annual meeting of the Transportation Research Board. - Washington DC.
-
Konferensbidrag (refereegranskat)abstract
- The purpose of this paper is to provide an analysis of potential benefits of a fleet of shared autonomous taxis “aTaxis”, in this paper referred to as Shared Autonomous Vehicles (SAV)) when replacing private car commuter trips in a metropolitan area. We develop a framework for dynamic allocation of SAVs to passenger trips, empty-vehicle routing and multi-criteria evaluation with regard to passenger waiting time, trip times and fleet size. Using a dynamic representation of current private vehicle demand for the Stockholm metropolitan area and a detailed network representation, different scenarios (varying levels of accepted passenger waiting time at origin and accepted % increase in travel time) are compared with respect to passenger travel time, number of vehicles needed and vehicle mileage. The results indicate that an SAV-based personal transport system has the potential to provide an on-demand door-to-door transport with a high level of service, using 5 % of today's private cars and parking places. In order to provide an environmental benefit and to reduce total mileage, an SAV-based personal transport system requires users to accept ride-sharing, allowing a maximum 30% increase of their travel time (13% on average) and a start time window of 10 minutes.
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| 23. |
- Burghout, Wilco, et al.
(författare)
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Incident management and traffic information : Simulation-based traffic prediction
- 2009
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Ingår i: 16th ITS World Congress.
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Konferensbidrag (refereegranskat)abstract
- Incident response and mitigation are the main tasks of operators at traffic control centres. Simulation models have a good chance of reproducing and predicting the effects of incident response by explicitly modelling drivers' responses to the incident and provided information. In the PREDIKT project, sponsored by the Swedish National Road Administration, a state-of-the-art mesoscopic simulation model (MEZZO) has been extended to provide decision support for incident management. In this paper we describe and test a number of essential modelling components such as modelling the incident response logic, a mixed-Logit model and a method for generation of alternative routes for drivers' route switching. In addition we present the results of a fast calibration method based on Simultaneous Perturbation Statistic Approximation (SPSA). The model components are tested in a small case study that investigates the impact of delay in information after incidents.
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| 24. |
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| 25. |
- Burghout, Wilco, et al.
(författare)
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Incident Management and Traffic Information Tools and Methods for Simulation-Based Traffic Prediction
- 2010
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Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; :2161, s. 20-28
-
Tidskriftsartikel (refereegranskat)abstract
- Incident response and mitigation are among the main tasks of operators at traffic control centers. Simulation models have a good chance of reproducing and predicting the effects of incident response by explicitly modeling driver response to the incident and information provided. In the PREDIKT project sponsored by the Swedish National Road Administration, the state-of-the-art mesoscopic simulation model MEZZO was extended to provide decision support for incident management. Numerous essential modeling components are described and tested, including modeling the incident response logic, a mixed-logit model, and a method for generating alternatives for drivers switching routes. In addition, the results of a fast calibration method based on simultaneous perturbation statistic approximation are presented. The model components are tested in a small case study that investigates the effect of delay in providing information to drivers after incidents. A linearization of speed-density functions also is shown to improve computational performance by 30% and increase calibration speed and stability while preserving simulation accuracy.
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| 26. |
- Burghout, Wilco, et al.
(författare)
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Multimodal Traffic Management : Project Report
- 2024
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Nya system för att kombinera transportsätt, till exempel Mobility as a Service (MaaS), ger nya möjligheter för trafikanter att växla mellan olika färdmedel. Samtidigt ger stora mängder data från såväl kollektivtrafiknätet som vägtrafiknätet samt multimodala data från mobilnäten i kombination med nya metoder för att uppskatta resmönster uppdelat på färdmedel möjligheter till en helt ny förståelse av multimodala resmönster i en stad. Att förstå hur multimodala resmönster utvecklas över tid ger nya möjligheter att utveckla effektiva verktyg för multimodal trafikledning.Det övergripande målet med projektet är att möjliggöra förbättrad tillgänglighet i transportsystemen genom effektivare trafikledning. Mer specifikt syftar projektet till att utveckla nya metoder för att uppskatta multimodal efterfrågan samt färdmedelsval och ruttval för multimodal trafikledning. Vidare har potentiella effekter av multimodal trafikledning analyserats.Projektet omfattar en litteraturstudie för analys av möjligheter och utmaningar med multimodal trafikledning. En explorativ analys baserad på oövervakat lärande har utförts för att identifiera typiska nätverksövergripande mobilitetsmönster. Val av rutt och färdmedel har predikterats med hjälp av statistiska modeller. Ett multimodalt dataset för fem veckor i Stockholm med storskalig mobilitetsdata för vägnätet och biljettdata för kollektivtrafiknätet har sammanställs för den explorativa analysen samt utvärderingen av rutt- och transportsättsmodellerna i samband med trafikledning.Baserat på litteraturstudien kan vi dra slutsatsen att koordinerad ledning av väg och kollektivtrafik har potential att minska trängseln och säkerställa effektiv förflyttning av resenärer i ett storstadsområde. Det finns flera motiv för multimodal trafikledning, där de viktigaste är potentiellt ökad efterfrågan för kollektivtrafik, förbättrad robusthet för transportsystemet och bättre prioritering av trafikledningsåtgärder. De största utmaningarna är samarbete mellan intressenter, informationsdelning och datafusion.Resultaten av den explorativa analysen baserad på oövervakad inlärning indikerar att klustring för att ta fram typdagar kan vara användbart vid scenarioutvärdering, men också fungera som input till korttidsprediktion, vilket ger en enkel och robust predikteringsmetod för länkflöden med ett MAPE-prediktionsfel på 10-15 %.Ruttvalsanalysen visar att en modell baserad på en ruttuppsättning med genererade rutter är mer responsiv för restidsförändringar än en modell baserad på endast observerade rutter, vilket är användbart för att förutspå effekten av olika trafikledningsåtgärder. En ruttvalsmodell med enbart restid är en vanlig förenkling att använda för att prediktera ruttval, men resultatet i denna studie visar att inkludering av fler attribut avsevärt förbättrar modellernas prestanda.Analysen av nätverksövergripande multimodala data för 5 veckor i Stockholm indikerar att det är möjligt att uppskatta hur transportsättsandelen mellan kollektivtrafik och andra transportslag varierar i tid och rum. En bättre förståelse för spatiotemporal variation av färdmedelsvalet är en viktig input till förbättrat beslutsstöd i multimodal trafikledning.
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| 27. |
- Burghout, Wilco, 1974-, et al.
(författare)
-
Vehicle loading in traffic simulation models
- 2007
-
Ingår i: Proceedings of the 86th Transportation Research Board Annual Meeting.
-
Konferensbidrag (refereegranskat)abstract
- Microscopic traffic simulation models are becoming increasingly popular and used to address a wide range of problems, from planning to operations. Furthermore, hybrid models that combine mesoscopic and microscopic models to simulate large scale networks are emerging. Despite the significant progress though, a potentially important process, the loading of vehicles onto the network, has not received much attention. If vehicles are assigned their initial speeds improperly, especially in congested networks, unnecessary turbulence may be created that will result in artificially reduced capacity of the loading link. The paper reviews existing loading methods (employed by the state of the art models MITSIMLab and VISSIM) and demonstrates the sensitivity of the simulation results to the initial speed. The results show that loading has a significant effect on the initial acceleration behavior of the loaded vehicles, and the (implied) capacity of the first segment of the entry link. The paper proposes four alternative loading approaches and identifies one as theoretically sound and consistent. A case study demonstrates that the new method is robust, and performs well even under congested conditions. The proposed method is useful not only for loading vehicles in microscopic models but also in the context of hybrid models for transferring vehicles from the meso to the micro network.
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| 28. |
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| 29. |
- Börjesson, M., et al.
(författare)
-
Trut - information search cost and benefits of traffic information (sweden)
- 2008
-
Ingår i: World Congr. Intell. Transp. Syst. ITS Am. Annu. Meet.. - 9781615677566 ; , s. 6685-6688
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Konferensbidrag (refereegranskat)abstract
- Benefits from traffic information examined using three methods; focus groups, stated preference-studies (SP) as well as simulated work-trips on the internet. The SP-results show that that there is a clear relationship between message content and the valuation. They also show that the value of decreasing uncertainty, when informed about a travel time delay with ± 10 minutes, corresponds to SEK 3.80 (EUR 0.4). The travel simulation shows that radio messages in general have a larger effect than VMS messages on route choice. Repeated information has however an impact, since a large share of the respondents who did not switch route at the first decision point, switched at the next decision point where updated information was given.
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| 30. |
- Cats, Oded, et al.
(författare)
-
Bus-Holding Control Strategies Simulation-Based Evaluation and Guidelines for Implementation
- 2012
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Ingår i: Transportation Research Record. - : National Academy of Sciences. - 0361-1981 .- 2169-4052. ; :2274, s. 100-108
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Tidskriftsartikel (refereegranskat)abstract
- Transit operations involve several inherent sources of uncertainty, including dispatch time from the origin terminal, travel time between stops, and dwell time at stops. Bus-holding control strategies are a prominent method applied by transit operators to improve transit performance and level of service. The common practice is to regulate departures from a limited number of stops by holding buses until their scheduled departure time. An analysis of the performance of a high-frequency bus line in Stockholm, Sweden, based on automatic vehicle location data showed that this control strategy was not effective in improving service regularity along the line. The analysis also indicated that drivers adjusted their speed according to performance objectives. Implications of a control strategy that regulates departures from all stops on the basis of the headways of the preceding bus and the following bus were evaluated with Bus Mezzo, a transit operations simulation model. The results suggest that this strategy can improve service performance considerably from both passengers' and operator's perspectives. In addition, the strategy implies cooperative operations, as the decisions of each driver are interdependent with other drivers' decisions, and mutual corrections can be made. Difficulties in realizing the benefits of the proposed strategy in practice, such as dispatching from the origin terminal, driver scheduling, and compliance, are discussed. The implications of several practical considerations are assessed by conducting a sensitivity analysis as part of the preparations for a field experiment designed to test the proposed control strategy.
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| 31. |
- Cats, Oded, et al.
(författare)
-
Effect of real-time transit information on dynamic passenger path choice.
- 2011
-
Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981. ; 2217, s. 46-54
-
Tidskriftsartikel (refereegranskat)abstract
- Real-time information is increasingly being implemented in transit networks worldwide. The evaluation of the effect of real-time information requires dynamic modeling of transit operations and of passenger path choices. This paper presents a dynamic transit analysis and evaluation tool that represents time-tables, operation strategies, real-time information, adaptive passenger choices, and traffic dynamics at the network level. Transit path choices are modeled as a sequence of boarding, walking and alighting decisions that passengers undertake when carrying out their journey. The model is applied to the Metro network of Stockholm, Sweden area under various operating conditions and information provision scenarios, as a proof of concept. An analysis of the results indicates substantial path choice shifts and potential time savings associated with more comprehensive real-time information provision and transfer coordination improvements.
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| 32. |
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| 33. |
- Cats, Oded, et al.
(författare)
-
Evaluation of real-time holding strategies for improved bus service reliability
- 2010
-
Ingår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC. - Madeira, Portugal. - 9781424476572 ; , s. 718-723
-
Konferensbidrag (refereegranskat)abstract
- Service reliability is one of the main measures of performance determining transit system level of service. Holding control strategies are a common transit operations practice aimed to reduce transit service unreliability by setting criteria for departure fromtime point stops. In order to adequately analyze the sources of uncertainty involved with transit performance, it is essential to model dynamically the interactions between traffic conditions, passenger demand and transit operations. BusMezzo, a transit simulation model has been developed on a platform of a mesoscopic traffic simulation model, which enables the representation of large-scale transit systems. The model implements severalreal-time holding strategies. It is used to evaluate the application of these strategies in areal-world high-demand bus line in the Tel Aviv metropolitan area, under various scenarios. An analysis of the results suggests that a holding strategy based on the mean headway from the preceding bus and the next bus, restricted by a maximum allowableholding time, is especially efficient.
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| 34. |
- Cats, Oded, et al.
(författare)
-
Impacts of holding control strategies on transit performance : A bus simulation model analysis
- 2011
-
Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; :2216, s. 51-58
-
Tidskriftsartikel (refereegranskat)abstract
- Transit operators are interested in strategies to improve service reliability as it is an important measure of performance and level of service. One of the common practices aimed at reducing service unreliability is holding control strategies. The design of these strategies involves the selection of a set of time point stops and the holding criteria for regulating the departure time. The interactions between passenger activity, transit operations, and traffic dynamics must be dynamically modeled to analyze the impacts of holding strategies on transit performance. An evaluation of different holding criteria and the number and location of time point stops was conducted with Bus Mezzo, a dynamic transit simulation model. The holding strategies were implemented in the model and applied to a high-frequency trunk bus line in Stockholm, Sweden. The analysis of the results considers the implications of holding strategies from both passenger and operator perspectives. The analysis suggests substantial gains are possible by implementing a holding strategy on the basis of the mean headway from the preceding and the succeeding buses. This strategy is the most efficient for passenger time savings as well as fleet costs and crew management.
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| 35. |
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| 36. |
- Cats, Oded, et al.
(författare)
-
Mesoscopic Modeling of Bus Public Transportation
- 2010
-
Ingår i: Transportation Research Record. - : SAGE Publications. - 0361-1981 .- 2169-4052. ; :2188, s. 9-18
-
Tidskriftsartikel (refereegranskat)abstract
- Analysis of public transport system performance and level of service in urban areas is essential. Dynamic modeling of traffic conditions, passenger demand, and transit operations is important to represent adequately the complexity of and the interactions between these components in modern public transportation systems. This paper presents a transit simulation model designed to support evaluation of operations planning and control, especially in the context of advanced public transportation systems. Unlike most previous efforts in this area, the simulation model is built on a platform of a mesoscopic traffic simulation model, which allows modeling or the operation dynamics of large-scale transit systems, taking into account the main sources of service uncertainty and stochasticity. The capabilities of Mezzo as an evaluation tool of transit operations are demonstrated with an application to a real-world, high-demand bus line in metropolitan Tel Aviv, Israel, under various scenarios. The application shows that important phenomena such as bus bunching are reproduced realistically. A comparison of simulated running times and headway distributions with field data shows the model is capable of replicating observed data.
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| 37. |
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| 38. |
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| 39. |
- Cebecauer, Matej, et al.
(författare)
-
3D Speed Maps and Mean Observations Vectors for Short-Term Urban Traffic Prediction
- 2019
-
Ingår i: TRB Annual Meeting Online. - Washington DC, US. ; , s. 1-20, s. 1-20
-
Konferensbidrag (refereegranskat)abstract
- City-wide travel time prediction in real-time is an important enabler for efficient use of the road network. It can be used in traveler information to enable more efficient routing of individual vehicles as well as decision support for traffic management applications such as directed information campaigns or incident management. 3D speed maps have been shown to be a promising methodology for revealing day-to-day regularities of city-level travel times and possibly also for short-term prediction. In this paper, we aim to further evaluate and benchmark the use of 3D speed maps for short-term travel time prediction and to enable scenario-based evaluation of traffic management actions we also evaluate the framework for traffic flow prediction. The 3D speed map methodology is adapted to short-term prediction and benchmarked against historical mean as well as against Probabilistic Principal Component Analysis (PPCA). The benchmarking and analysis are made using one year of travel time and traffic flow data for the city of Stockholm, Sweden. The result of the case study shows very promising results of the 3D speed map methodology for short-term prediction of both travel times and traffic flows. The modified version of the 3D speed map prediction outperforms the historical mean prediction as well as the PPCA method. Further work includes an extended evaluation of the method for different conditions in terms of underlying sensor infrastructure, preprocessing and spatio-temporal aggregation as well as benchmarking against other prediction methods.
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| 40. |
- Cebecauer, Matej
(författare)
-
Enhancing Short-Term Traffic Prediction for Large-Scale Transport Networks by Spatio-Temporal Clustering
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Congestion in large cities is responsible for extra travel time, noise, air pollution, CO2 emissions, and more. Transport is one of the main recognized contributors to global warming and climate change, which is getting increasing attention from authorities and societies around the world. Better utilization of existing resources by Intelligent Transport Systems (ITS) and digital technologies are recognized by the European Commission as technologies with enormous potential to lower the negative impacts associated with high traffic volumes in urban areas.The main focus of this work is on short-term traffic prediction, which is an essential tool in ITS. In combination with providing information, it enables proactive decisions to decrease severity of congestion that occurs regularly or is caused by incidents. The main contribution of this work is to develop a methodological framework and prove its enhancing effects on short-term prediction in the context of large-scale transport networks. It is expected to contribute to more robust and accurate predictions of ITS in traffic management centers.Traffic patterns in large-scale networks, including urban streets, can be heterogeneous during the day and from day-to-day. This work investigates spatio-temporal clustering of heterogeneous data sets to smaller, more homogeneous data sub-sets. This is expected to produce more robust, accurate, scalable, and cost-effective prediction models. This thesis is the collection of five papers that contribute to enhancing short-term traffic prediction in this context. The clustering is recognized to boost prediction performance in Papers II, III, IV, and V. Paper II considers network partitioning and the last three papers study day clustering. The prediction models used across included papers are naive historical mean prediction models and more advanced prediction models such as probabilistic principal component analysis (PPCA) and exponential smoothing. Paper I considers and facilitates floating car data (FCD) as a cost-effective opportunistic source of speed and travel time data with extensive network coverage.Common practice in determining the number of clusters is to rely on internal evaluation indices, and these are very efficient but isolated from application. Paper IV tests this practice by also considering performance in short-term prediction application. Our results show that relying on these indices can lead to a loss of prediction accuracy of about 20% depending on the considered prediction model. Dimensionality reduction has a minimal effect on the resulting prediction performance, but clustering needs 20 times less computational time and only 0.1% of the original information.Finally, in Paper V, we look at similarities of representative day clusters recognized by speed and flows. Furthermore, the interchangeability of speed day-type centroids for flow when predicting speeds has proven to be robust, which is not a case for predicting flows by speed day-type centroids and observations.
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| 41. |
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| 42. |
- Cebecauer, Matej, et al.
(författare)
-
Integrated framework for real-time urban network travel time prediction on sparse probe data
- 2018
-
Ingår i: IET Intelligent Transport Systems. - : Institution of Engineering and Technology. - 1751-956X .- 1751-9578. ; 12:1, s. 66-74
-
Tidskriftsartikel (refereegranskat)abstract
- The study presents the methodology and system architecture of an integrated urban road network travel time prediction framework based on low-frequency probe vehicle data. Intended applications include real-time network traffic management, vehicle routing and information provision. The framework integrates methods for receiving a stream of probe vehicle data, map matching and path inference, link travel time estimation, calibration of prediction model parameters and network travel time prediction in real time. The system design satisfies three crucial aspects: computational efficiency of prediction, internal consistency between components and robustness against noisy and missing data. Prediction is based on a multivariate hybrid method of probabilistic principal component analysis, which captures global correlation patterns between links and time intervals, and local smoothing, which considers local correlations among neighbouring links. Computational experiments for the road network of Stockholm, Sweden and probe data from taxis show that the system provides high accuracy for both peak and off-peak traffic conditions. The computational efficiency of the framework makes it capable of real-time prediction for large-scale networks. For links with large speed variations between days, prediction significantly outperforms the historical mean. Furthermore, prediction is reliable also for links with high proportions of missing data.
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| 43. |
- Cebecauer, Matej, et al.
(författare)
-
Integrating Demand Responsive Services into Public Transport Disruption Management
- 2021
-
Ingår i: IEEE Open Journal of Intelligent Transportation Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 2687-7813. ; 2, s. 24-36
-
Tidskriftsartikel (refereegranskat)abstract
- High-capacity public transport services such as metro and commuter trains are efficient during normal operations but are vulnerable to disruptions. To manage disruptions, bridging buses are commonly called in to replace the rail-based service along the disrupted lines. These often take significant time to arrive and are costly to keep stand-by. Demand-responsive transport such as taxi can respond to demand almost immediately but is costly and must usually be arranged by the individual travelers. This study examines the integration and potential role of demand-responsive transport in disruption management. The analysis considers the impacts of limiting the serving area, varying the number of available vehicles, pursuing ride-sharing, as well as a system-of-systems approach with collaboration between taxis and bridging buses. Results of computational experiments on the case study of Stockholm, Sweden reveal that integration of demand-responsive transport in the disruption management can bring large positive benefits in terms of average and maximum waiting times for travelers. This is especially the case for strategies including ridesharing. It is also shown that appropriate trade-offs between desired waiting times and costs can be achieved by collaboration of both bridging buses and demand-responsive transport. Additionally, more robust public transport with increased reliability during disruptions can increase sustainability as more people may choose public transport instead of private cars.
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| 44. |
- Cebecauer, Matej, et al.
(författare)
-
Public transport disruption management by collaboration with demand responsive services
- 2020
-
Konferensbidrag (refereegranskat)abstract
- For large cities, public transport represents the backbone for commuters and thus plays a crucial role for society and for the economy. High-capacity public transport services such as metro and commuter trains are efficient during normal operations but are vulnerable to disruptions. Metro and commuter train disruptions can be handled in several ways. Very common are bridging buses that are called in to replace the rail-based service along the disrupted lines. These often take significant time to arrive and are costly to keep stand-by. Demand-responsive transport such as taxi can respond to demand almost immediately but is costly and must usually be arranged by the individual travelers. This study examines the integration and potential role of demand-responsive transport in disruption management. The analysis considers the impacts of limiting the serving area, varying the number of available vehicles, pursuing ridesharing, as well as a system-of-systems approach with collaboration between taxis and bridging buses. Results of computational experiments on the case study of Stockholm, Sweden reveal that integration of demand-responsive transport in the disruption management can bring large positive benefits in terms of average and maximum waiting times for travelers. This is especially the case for strategies including ridesharing. It is also shown that appropriate trade-offs between desired waiting times and costs can be achieved by collaboration of both bridging buses and demand-responsive transport. Additionally, it is expected that more robust public transport with increased reliability during disruptions can increase sustainability as more people may choose public transport instead of private cars.
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| 45. |
- Cebecauer, Matej, et al.
(författare)
-
Real-time city-level traffic prediction in the context of Stockholm City
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: The ongoing POST (Prediktions- och Scenariobaserad Trafikledning) project and the previous project Mobile Millennium Stockholm (MMS) provided tools and frameworks for real-time estimation and prediction of travel times on the city-level. City-level prediction of the traffic state as well as the traffic demand is important for both traveler information applications, such as online navigation, and traffic management applications, such as scenario evaluation of incident management strategies. However, city-level prediction is very challenging and requires efficient processing of large amounts of data. Here we present the recent research about effects of the clustering on the prediction performance and computational cost. Partitioning of the road network based on spatial and temporal attributes can potentially result in clusters that provide more robust and accurate prediction with reasonable bias-variance tradeoff. Methods: The effects of the clustering on the prediction performance are studied on the three case studies, representing different travel time sources in Stockholm city. First represent 15 MCS radars as the sources of travel times. Second 420 segments on the major roads around Stockholm with travel times estimated from the MCS radars. Third, travel times of 11,340 links processed from GPS data of 1,500 taxis operating in Stockholm. With the computational experiments, we studied different clustering approaches based on the day classification, functional classes, spatial locations and temporal attributes, and how they can effect the prediction performance and computational cost.Results: reveal that partitioning can significantly improve the prediction accuracy and rapidly decrease the computational cost and time.
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| 46. |
- Cebecauer, Matej, et al.
(författare)
-
Revealing representative day-types in transport networks using traffic data clustering
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Recognition of spatio-temporal traffic patterns at the network-wide level plays an important role in data-driven intelligent transport systems (ITS) and is a basis for applications such as short-term prediction and scenario-based traffic management. Common practice in the transport literature is to rely on well-known general unsupervised machine-learning methods (e.g., k-means, hierarchical, spectral, DBSCAN) to select the most representative structure and number of day-types based solely on internal evaluation indices. These are easy to calculate but are limited since they only use information in the clustered dataset itself. In addition, the quality of clustering should ideally be demonstrated by external validation criteria, by expert assessment or the performance in its intended application. The main contribution of this paper is to test and compare the common practice of internal validation with external validation criteria represented by the application to short-term prediction, which also serves as a proxy for more general traffic management applications. When compared to external evaluation using short-term prediction, internal evaluation methods have a tendency to underestimate the number of representative day-types needed for the application. Additionally, the paper investigates the impact of using dimensionality reduction. By using just 0.1\% of the original dataset dimensions, very similar clustering and prediction performance can be achieved, with up to 20 times lower computational costs, depending on the clustering method. K-means and agglomerative clustering may be the most scalable methods, using up to 60 times fewer computational resources for very similar prediction performance to the p-median clustering.
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| 47. |
- Cebecauer, Matej, et al.
(författare)
-
Revealing representative day-types in transport networks using traffic data clustering
- 2023
-
Ingår i: Journal of Intelligent Transportation Systems / Taylor & Francis. - : Informa UK Limited. - 1547-2450 .- 1547-2442. ; , s. 1-24
-
Tidskriftsartikel (refereegranskat)abstract
- Recognition of spatio-temporal traffic patterns at the network-wide level plays an important role in data-driven intelligent transport systems (ITS) and is a basis for applications such as short-term prediction and scenario-based traffic management. Common practice in the transport literature is to rely on well-known general unsupervised machine-learning methods (e.g., k-means, hierarchical, spectral, DBSCAN) to select the most representative structure and number of day-types based solely on internal evaluation indices. These are easy to calculate but are limited since they only use information in the clustered dataset itself. In addition, the quality of clustering should ideally be demonstrated by external validation criteria, by expert assessment or the performance in its intended application. The main contribution of this paper is to test and compare the common practice of internal validation with external validation criteria represented by the application to short-term prediction, which also serves as a proxy for more general traffic management applications. When compared to external evaluation using short-term prediction, internal evaluation methods have a tendency to underestimate the number of representative day-types needed for the application. Additionally, the paper investigates the impact of using dimensionality reduction. By using just 0.1% of the original dataset dimensions, very similar clustering and prediction performance can be achieved, with up to 20 times lower computational costs, depending on the clustering method. K-means and agglomerative clustering may be the most scalable methods, using up to 60 times fewer computational resources for very similar prediction performance to the p-median clustering.
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| 48. |
- Cebecauer, Matej, 1986-
(författare)
-
Short-Term Traffic Prediction in Large-Scale Urban Networks
- 2019
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- City-wide travel time prediction in real-time is an important enabler for efficient use of the road network. It can be used in traveler information to enable more efficient routing of individual vehicles as well as decision support for traffic management applications such as directed information campaigns or incident management. 3D speed maps have been shown to be a promising methodology for revealing day-to-day regularities of city-level travel times and possibly also for short-term prediction. In this paper, we aim to further evaluate and benchmark the use of 3D speed maps for short-term travel time prediction and to enable scenario-based evaluation of traffic management actions we also evaluate the framework for traffic flow prediction. The 3D speed map methodology is adapted to short-term prediction and benchmarked against historical mean as well as against Probabilistic Principal Component Analysis (PPCA). The benchmarking and analysis are made using one year of travel time and traffic flow data for the city of Stockholm, Sweden. The result of the case study shows very promising results of the 3D speed map methodology for short-term prediction of both travel times and traffic flows. The modified version of the 3D speed map prediction outperforms the historical mean prediction as well as the PPCA method. Further work includes an extended evaluation of the method for different conditions in terms of underlying sensor infrastructure, preprocessing and spatio-temporal aggregation as well as benchmarking against other prediction methods.
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| 49. |
- Cebecauer, Matej, et al.
(författare)
-
Similarity and Interchangeability of Flow and Speed Data for Transport Network Day-Type Clustering and Prediction
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Prediction of future traffic states is an essential part of traffic management and intelligent transportation systems. Previous work has shown that spatio-temporal clustering of traffic data such as flows or speeds into network day-types improves both the performance and the robustness of traffic predictions. Since some data types may not be available at a network-wide level, or only for certain periods, this paper investigates how similar such representative day-types are if based on different data types. The similarity of day-type clusters is evaluated with qualitative calendar visualization and two quantitative metrics, the Adjusted Mutual Information (AMI) which considers day-to-cluster assignments, and a new proposed Centroids Similarity Score (CSS) which compares centroids. The paper also explores the impact on flow and speed prediction performance of substituting one data type for the other in the clustering or classification phases. Using microwave sensor data from the Stockholm motorway network, our findings show that clusterings based on flows and speeds and across a range of clustering methods have reasonably high similarity. CSS is found to be a more relevant similarity indicator than AMI in the prediction application context. By capturing more relevant traffic state information, flow-based clustering and classification are robust for both flow and speed predictions, while speed-based clustering significantly degrades flow prediction performance.
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| 50. |
- Cebecauer, Matej, et al.
(författare)
-
Spatio-Temporal Partitioning of Large Urban Networks for Travel Time Prediction
- 2018
-
Ingår i: 2018 21ST INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC). - : IEEE. - 9781728103235 ; , s. 1390-1395
-
Konferensbidrag (refereegranskat)abstract
- The paper explores the potential of spatiotemporal network partitioning for travel time prediction accuracy and computational costs in the context of large-scale urban road networks (including motorways/freeways, arterials and urban streets). Forecasting in this context is challenging due to the complexity, heterogeneity, noisy data, unexpected events and the size of the traffic network. The proposed spatio-temporal network partitioning methodology is versatile, and can be applied for any source of travel time data and multivariate travel time prediction method. A case study of Stockholm, Sweden considers a network exceeding 11,000 links and uses taxi probe data as the source of travel times data. To predict the travel times the Probabilistic Principal Component Analysis (PPCA) is used. Results show that the spatio-temporal network partitioning provides a more appropriate bias-variance tradeoff, and that prediction accuracy and computational costs are improved by considering the proper number of clusters towards robust large-scale travel time prediction.
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