| 1. |
- Allström, Andreas, 1978-, et al.
(författare)
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A hybrid approach for short-term traffic state and travel time prediction on highways
- 2016
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Ingår i: TRB 95th annual meeting compendium of papers.
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Konferensbidrag (refereegranskat)abstract
- Traffic management and traffic information are essential in urban areas, and require a good knowledge about both the current and the future traffic state. Both parametric and non-parametric traffic state prediction techniques have previously been developed, with different advantages and shortcomings. While non-parametric prediction has shown good results for predicting the traffic state during recurrent traffic conditions, parametric traffic state prediction can be used during non-recurring traffic conditions such as incidents and events. Hybrid approaches, combining the two prediction paradigms have previously been proposed by using non-parametric methods for predicting boundary conditions used in a parametric method. In this paper we instead combine parametric and non-parametric traffic state prediction techniques through assimilation in an Ensemble Kalman filter. As non-parametric prediction method a neural network method is adopted, and the parametric prediction is carried out using a cell transmission model with velocity as state. The results show that our hybrid approach can improve travel time prediction of journeys planned to commence 15 to 30 minutes into the future, using a prediction horizon of up to 50 minutes ahead in time to allow the journey to be completed.
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| 2. |
- Allström, Andreas, 1978-, et al.
(författare)
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Evaluation of travel time estimation based on LWR-v and CTM-v : A case study in Stockholm
- 2012
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Ingår i: 15th International IEEE Conference on Intelligent Transportation Systems (ITSC), 2012. - Piscataway, N.J, USA : IEEE. - 9781467330640 - 9781467330626 ; , s. 1644-1649
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Konferensbidrag (refereegranskat)abstract
- Real-time estimations of current and future traffic states are an essential part of traffic management and traffic information systems. Within the Mobile Millennium project considerable effort has been invested in the research and development of a real-time estimation system that can fuse several sources of data collected in California. During the past year this system has been adapted to also handle traffic data collected in Stockholm. This paper provides an overview of the model used for highways and presents results from an initial evaluation of the system. As part of the evaluation process, GPS data collected in an earlier field-test and estimations generated by the existing system used by the TMC in Stockholm, are compared with the estimations generated by the Mobile Millennium system. Given that the Mobile Millennium Stockholm system has not undergone any calibration, the results from the evaluation are considered promising. The estimated travel times correspond well to those measured in the field test. Furthermore, the estimations generated by the Mobile Millennium system can be regarded as superior to those of existing traffic management system in Stockholm. The highway model was found to perform well even with a reduction in the number of sensors providing data. The findings of this study indicate the robustness of the Mobile Millennium system and demonstrate how the system can be migrated to other geographical areas with similar sources of available data.
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| 3. |
- Allström, Andreas, 1978-, et al.
(författare)
-
Hybrid Approach for Short-Term Traffic State and Travel Time Prediction on Highways
- 2016
-
Ingår i: Transportation Research Record. - Washington, DC, USA : The National Academies of Sciences, Engineering, and Medicine. - 0361-1981 .- 2169-4052. ; 2554, s. 60-68
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Tidskriftsartikel (refereegranskat)abstract
- Traffic management and traffic information are essential in urban areas and require reliable knowledge about the current and future traffic state. Parametric and nonparametric traffic state prediction techniques have previously been developed with different advantages and shortcomings. While nonparametric prediction has shown good results for predicting the traffic state during recurrent traffic conditions, parametric traffic state prediction can be used during nonrecurring traffic conditions, such as incidents and events. Hybrid approaches have previously been proposed; these approaches combine the two prediction paradigms by using nonparametric methods for predicting boundary conditions used in a parametric method. In this paper, parametric and nonparametric traffic state prediction techniques are instead combined through assimilation in an ensemble Kalman filter. For nonparametric prediction, a neural network method is adopted; the parametric prediction is carried out with a cell transmission model with velocity as state. The results show that the hybrid approach can improve travel time prediction of journeys planned to commence 15 to 30 min into the future, with a prediction horizon of up to 50 min ahead in time to allow the journey to be completed
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| 4. |
- Allström, Andreas, 1978-, et al.
(författare)
-
Mobile Millennium Stockholm
- 2011
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Ingår i: 2nd International Conference on Models and Technologies for Intelligent Transportation Systems.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Grumert, Ellen, 1983-, et al.
(författare)
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Variabla hastighetsgränser för Stockholms motorvägsnät : Effekter av alternativa algoritmer och möjligheter till styrning genom skattade trafiktillstånd
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Variabla hastighetsgränser är väl utbrett på Stockholms stadsnära motorvägar och en del av Stockholms Motorway Control System (MCS). Målet med dagens system är att minska risken för olyckor och följdolyckor vid låga hastigheter, trafikstockningar m.m. Detta görs genom att mäta medelhastigheten med hjälp av fasta detektorer och uppdatera hastigheten som visas på variabla meddelandeskyltar utifrån rådande trafiktillstånd. I och med att efterfrågan på resor i Stockholm under rusningstid överstiger den tillgängliga kapaciteten i vägnätet är behovet av ett effektivt trafiksystem stort. Variabla hastighetsgränser kan bidra till ökad framkomlighet, men då dagens system har som målsättning att öka säkerheten är effekter som leder till ökad framkomlighet begränsade. Dessutom finns det i dagens system ett stort beroende av fungerande detektorer som mäter trafiktillståndet så korrekt som möjligt för att valet av hastighet ska kunna bestämmas på ett effektivt sätt.Syftet med den här rapporten är att undersöka alternativa styralgoritmer för att bestämma variabla hastighetsgränser på Stockholms motorvägsnät. Målet är att öka framkomligheten jämfört med dagens system. Två olika sträckor med olika komplexitet, trafiksituation och problematik studeras. Valet av studerade styralgoritmer för de olika sträckorna väljs för att på bästa sätt motverka den problematiken som uppstår på de specifika sträckorna. Därmed kan val av algoritmer komma att skilja sig åt beroende på sträcka. I projektet utvärderas också om estimering av trafiktillståndet kan användas för att förbättra informationsflödet till algoritmerna då detektorer inte fungerar som de ska eller helt saknas, vilket i sin tur kan leda till förbättrad anpassning av de variabla hastighetsgränserna. Detta görs av för en av de studerade sträckorna. Styralgoritmerna utvärderas med mikroskopisk trafiksimulering och metoden utvecklad i projektet Mobile Millenium Stockholm (MMS), som bygger på en makroskopisk trafikflödesmodell och Kalman filtrering, används för estimering av trafiktillståndet.Resultatet visar att det finns styralgoritmer med potential att öka framkomligheten. Valet av styralgoritm är dock beroende av typ av trafiksituation, vägdesignens komplexitet och trafikförhållanden på vägen. Det betyder att olika styralgoritmer kan prestera olika bra beroende på vilken vägsträcka man studerar. Vidare är estimering av trafiktillståndet användbart vid förlorad information på grund av icke-fungerande detektorer eller som komplement till detektorer för att minska mängden stationär utrustning.
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| 6. |
- Gundlegård, David, 1978-, et al.
(författare)
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Travel Time and Point Speed Fusion Based on a Macroscopic Traffic Model and Non-linear Filtering
- 2015
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Ingår i: 2015 IEEE 18th International Conference on Intelligent Transportation Systems. - : IEEE conference proceedings. - 9781467365956 ; , s. 2121-2128
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Konferensbidrag (refereegranskat)abstract
- The number and heterogeneity of traffic sensors are steadily increasing. A large part of the emerging sensors are measuring point speeds or travel times and in order to make efficient use of this data, it is important to develop methods and frameworks for fusion of point speed and travel time measurements in real-time. The proposed method combines a macroscopic traffic model and a non-linear filter with a new measurement model for fusion of travel time observations in a system that uses the velocity of cells in the network as state vector. The method aims to improve the fusion efficiency, especially when travel time observations are relatively long compared to the spatial resolution of the estimation framework. The method is implemented using the Cell Transmission Model for velocity (CTM-v) and the Ensemble Kalman Filter (EnKF) and evaluated with promising results in a test site in Stockholm, Sweden, using point speed observations from radar and travel time observations from taxis.
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| 7. |
- Angelakis, Vangelis, et al.
(författare)
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Mobility modeling for transport efficiency : Analysis of travel characteristics based on mobile phone data
- 2013
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Ingår i: Netmob 2013.
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Konferensbidrag (refereegranskat)abstract
- Signaling data from the cellular networks can provide a means of analyzing the efficiency of a deployed transportation system and assisting in the formulation of transport models to predict its future use. An approach based on this type of data can be especially appealing for transportation systems that need massive expansions, since it has the added benefit that no specialized equipment or installations are required, hence it can be very cost efficient.Within this context in this paper we describe how such obtained data can be processed and used in order to act as enablers for traditional transportation analysis models. We outline a layered, modular architectural framework that encompasses the entire process and present results from initial analysis of mobile phone call data in the context of mobility, transport and transport infrastructure. We finally introduce the Mobility Analytics Platform, developed by Ericsson Research, tailored for mobility analysis, and discuss techniques for analyzing transport supply and demand, and give indication on how cell phone use data can be used directly to analyze the status and use of the current transport infrastructure.
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| 8. |
- Breyer, Nils, 1988-
(författare)
-
Analysis of Travel Patterns from Cellular Network Data
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traffic planners are facing a big challenge with an increasing demand for mobility and a need to drastically reduce the environmental impacts of the transportation system at the same time. The transportation system therefore needs to become more efficient, which requires a good understanding about the actual travel patterns. Data from travel surveys and traffic counts is expensive to collect and gives only limited insights on travel patterns. Cellular network data collected in the mobile operators infrastructure is a promising data source which can provide new ways of obtaining information relevant for traffic analysis. It can provide large-scale observations of travel patterns independent of the travel mode used and can be updated easier than other data sources. In order to use cellular network data for traffic analysis it needs to be filtered and processed in a way that preserves privacy of individuals and takes the low resolution of the data in space and time into account. The research of finding appropriate algorithms is ongoing and while substantial progress has been achieved, there is a still a large potential for better algorithms and ways to evaluate them.The aim of this thesis is to analyse the potential and limitations of using cellular network data for traffic analysis. In the three papers included in the thesis, contributions are made to the trip extraction, travel demand and route inference steps part of a data-driven traffic analysis processing chain. To analyse the performance of the proposed algorithms, a number of datasets from different cellular network operators are used. The results obtained using different algorithms are compared to each other as well as to other available data sources.A main finding presented in this thesis is that large-scale cellular network data can be used in particular to infer travel demand. In a study of data for the municipality of Norrköping, the results from cellular network data resemble the travel demand model currently used by the municipality, while adding more details such as time profiles which are currently not available to traffic planners. However, it is found that all later traffic analysis results from cellular network data can differ to a large extend based on the choice of algorithm used for the first steps of data filtering and trip extraction. Particular difficulties occur with the detection of short trips (less than 2km) with a possible under-representation of these trips affecting the subsequent traffic analysis.
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| 9. |
- Breyer, Nils, 1988-, et al.
(författare)
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Cellpath Routing and Route Traffic Flow Estimation Based on Cellular Network Data
- 2018
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Ingår i: The Journal of urban technology. - : Taylor & Francis. - 1063-0732 .- 1466-1853. ; :2, s. 85-104
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Tidskriftsartikel (refereegranskat)abstract
- The signaling data in cellular networks provide means for analyzing the use of transportation systems. We propose methods that aim to reconstruct the used route through a transportation network from call detail records (CDRs) which are spatially and temporally sparse. The route estimation methods are compared based on the individual routes estimated. We also investigate the effect of different route estimation methods when employed in a complete network assignment for a larger city. Using an available CDR dataset for Dakar, Senegal, we show that the choice of the route estimation method can have a significant impact on resulting link flows.
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| 10. |
- Breyer, Nils, 1988-, et al.
(författare)
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Comparative Analysis of Travel Patterns from Cellular Network Data and an Urban Travel Demand Model
- 2020
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Ingår i: Journal of Advanced Transportation. - : John Wiley & Sons. - 0197-6729 .- 2042-3195.
-
Tidskriftsartikel (refereegranskat)abstract
- Data on travel patterns and travel demand are an important input to today’s traffic models used for traffic planning. Traditionally, travel demand is modelled using census data, travel surveys, and traffic counts. Problems arise from the fact that the sample sizes are rather limited and that they are expensive to collect and update the data. Cellular network data are a promising large-scale data source to obtain a better understanding of human mobility. To infer travel demand, we propose a method that starts by extracting trips from cellular network data. To find out which types of trips can be extracted, we use a small-scale cellular network dataset collected from 20 mobile phones together with GPS tracks collected on the same device. Using a large-scale dataset of cellular network data from a Swedish operator for the municipality of Norrköping, we compare the travel demand inferred from cellular network data to the municipality’s existing urban travel demand model as well as public transit tap-ins. The results for the small-scale dataset show that, with the proposed trip extraction methods, the recall (trip detection rate) is about 50% for short trips of 1-2 km, while it is 75–80% for trips of more than 5 km. Similarly, the recall also differs by a travel mode with more than 80% for public transit, 74% for car, but only 53% for bicycle and walking. After aggregating trips into an origin-destination matrix, the correlation is weak () using the original zoning used in the travel demand model with 189 zones, while it is significant with when aggregating to 24 zones. We find that the choice of the trip extraction method is crucial for the travel demand estimation as we find that the choice of the trip extraction method is crucial for the travel demandestimation as we find systematic differences in the resulting travel demand matrices using two different methods.
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| 11. |
- Breyer, Nils, 1988-
(författare)
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Methods for Travel Pattern Analysis Using Large-Scale Passive Data
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Comprehensive knowledge of travel patterns is crucial to enable planning for a more efficient traffic system that accommodates human mobility demand. Currently, this knowledge is mainly based on traffic models based on relatively small samples of observations collected from travel surveys and traffic counts. The data is expensive to collect and provides only partial observations of travel patterns. With the rise of new technology, new largescale passive data sources can be used to analyse travel patterns. This thesis aims to expand the knowledge about how to use cellular network data collected by cellular network operators and smart-card data from public transit systems to analyse travel patterns. The focus is particularly on the data processing methods needed to extract travel patterns. The thesis’s contributions include new methods for extracting trips, estimating travel demand, route inference and travel mode choice from cellular network data and a method to extract travel behaviour changes from smart-card data. Different approaches are proposed to evaluate the methods: the validation using experimental data, validation using other available data sources, and comparison of results obtained using different methods. The findings include that methods for extracting travel patterns from largescale passive data need to account for the data’s characteristics. Paper II illustrates that route inference from Call Detail Records by strictly following the used cell towers’ locations is problematic due to the noise and low resolution of the data. Both rule-based and machine learning methods can be used to extract travel patterns. Paper I shows that a rule-based stop detection algorithm can be used to extract longer trips from cellular network data reliably. On the other hand, Paper III shows that for travel mode classification of trips extracted from cellular network data, supervised classification can outperform rule-based methods. Unsupervised machine learning can be used to find patterns without prior specification. Paper V shows how clustering of smart-card data could be used to group public transit users by travel behaviour to understand the effects of a disruption. Supervised machine learning requires training data. When no or little training data is available, using semi-supervised learning is a promising approach as demonstrated in Paper IV. In the studies of this thesis, real-world, large-scale passive datasets have been used to demonstrate how the extraction of travel patterns works under realistic circumstances. This has exposed limitations due to the data source’s characteristics and limitations due to possible sample bias. At the same time, the studies of this thesis show the potential of using large-scale passive data. Changes in travel patterns can be identified quickly as new data can be collected continuously. Due to the large sample size, the data allows understanding travel patterns based on observations instead of relying on traffic models’ underlying assumptions.
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| 12. |
- Breyer, Nils, 1988-, et al.
(författare)
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Semi-supervised Mode Classification of Inter-city Trips from Cellular Network Data
- 2022
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Ingår i: Journal of Big Data Analytics in Transportation. - : Springer. - 2523-3564 .- 2523-3556. ; :1, s. 23-39
-
Tidskriftsartikel (refereegranskat)abstract
- Good knowledge of travel patterns is essential in transportation planning. Cellular network data as a large-scale passive data source provides billions of daily location updates allowing us to observe human mobility with all travel modes. However, many transport planning applications require an understanding of travel patterns separated by travel mode, requiring the classification of trips by travel mode. Most previous studies have used rule-based or geometric classification, which often fails when the routes for different modes are similar or supervised classification, requiring labelled training trips. Sufficient amounts of labelled training trips are unfortunately often unavailable in practice. We propose semi-supervised classification as a novel approach of classifying large sets of trips extracted from cellular network data in inter-city origin–destination pairs as either using road or rail. Our methods require no labelled trips which is an important advantage as labeled data is often not available in practice. We propose three methods which first label a small share of trips using geometric classification. We then use structures in a large set of unlabelled trips using a supervised classification method (geometric-labelling), iterative semi-supervised training (self-labelling) and by transferring information between origin–destination pairs (continuity-labelling). We apply the semi-supervised classification methods on a dataset of 9545 unlabelled trips in two inter-city origin–destination pairs. We find that the methods can identify structures in the cells used during trips in the unlabelled data corresponding to the available route alternatives. We validate the classification methods using a dataset of 255 manually labelled trips in the two origin–destination pairs. While geometric classification misclassifies 4.2% and 5.6% of the trips in the two origin–destination pairs, all trips can be classified correctly using semi-supervised classification.
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| 13. |
- Breyer, Nils, 1988-, et al.
(författare)
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Travel mode classification of intercity trips using cellular network data
- 2021
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Ingår i: Transportation Research Procedia. - Paphos, Cyprus : Elsevier. ; , s. 211-218
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Konferensbidrag (refereegranskat)abstract
- Many applications in transport planning require an understanding of travel patterns separated by travel mode. To use cellular network data as observations of human mobility in these applications, classification by travel mode is needed. Existing classification methods for GPS-trajectories are often inefficient for cellular network data, which has lower resolution in space and time than GPS data.In this study, we compare three geometry-based mode classification methods and three supervised methods to classify trips extracted from cellular network data in intercity origin-destination pairs as either road or train. To understand the difficulty of the problem, we use a labeled dataset of 255 trips in two OD-pairs to train the supervised classification methods and to evaluate the classification performance. For an OD-pair where the road and train routes are not separated by more than four kilometers, the geometry-based methods classify 4.5% - 7.1% of the trips wrong, while two of the supervised methods can classify all trips correctly. Using a large-scale dataset of 29037 trips, we find that separation between classes is less evident than in the labeled dataset and show that the choice of classification methods impacts the aggregated modal split estimate.
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| 14. |
- Breyer, Nils, 1988-, et al.
(författare)
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Trip extraction for traffic analysis using cellular network data
- 2017
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Ingår i: 5th IEEE International Conference on Models and Technologies for Intelligent Transportation Systems (MT-ITS). - Naples : IEEE Press. - 9781509064847 ; , s. 321-326
-
Konferensbidrag (refereegranskat)abstract
- To get a better understanding of people’s mobility, cellular network signalling data including location information, is a promising large-scale data source. In order to estimate travel demand and infrastructure usage from the data, it is necessary to identify the trips users make. We present two trip extraction methods and compare their performance using a small dataset collected in Sweden. The trips extracted are compared with GPS tracks collected on the same mobiles. Despite the much lower location sampling rate in the cellular network signalling data, we are able to detect most of the trips found from GPS data. This is promising, given the relative simplicity of the algorithms. However, further investigation is necessary using a larger dataset and more types of algorithms. By applying the same methods to a second dataset for Senegal with much lower sampling rate than the Sweden dataset, we show that the choice of the trip extraction method tends to be even more important when the sampling rate is low.
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| 15. |
- Brusselaers, Nicolas, PhD, 1993-, et al.
(författare)
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Decision support for improved construction traffic management and planning
- 2024
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Ingår i: Sustainable cities and society. - : Elsevier. - 2210-6707. ; 104
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Tidskriftsartikel (refereegranskat)abstract
- Densifying cities continuously call for new construction, renovation and demolition projects, each generating vast amounts of heavy goods vehicle (HGV) transports. However, how construction transportation affects the urban traffic network remains largely unexplored. This study addresses spatiotemporal network impacts from construction transport, by leveraging traditional traffic and transport simulation. To this end, a framework is presented including (i) a simulation model to compute traffic effects caused by varying off-site construction site transport demands, and (ii) conceptual applications of the simulation model showing construction logistic planning strategies to mitigate congestion disturbances. Simulations are conducted in MATSim using detailed secondary datasets describing site-specific transport arrivals from a case of six projects in Norrköping, Sweden. Subsequently, increasing transport demands were assessed on various time-window arrival scenarios against the baseline schedule, which can be used as decision support in urban planning. Results highlight how rigorous construction transport planning avoiding peak-traffic hours can significantly alleviate traffic congestion. This study also emphasizes the need to combine all simultaneous construction projects’ demands when evaluating disturbances on city-level, alongside the impact on individual links and microenvironments. This study adds knowledge by visualizing the traffic impact during urban transformation.
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| 16. |
- Cebecauer, Matej, et al.
(författare)
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3D Speed Maps and Mean Observations Vectors for Short-Term Urban Traffic Prediction
- 2019
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Ingår i: TRB Annual Meeting Online. - Washington DC, US. ; , s. 1-20, s. 1-20
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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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| 17. |
- Danielsson, Anna, 1995-, et al.
(författare)
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Analysis of Route Sets and Attributes in Route Choice Estimation for Urban Traffic Management Using GPS Data
- 2024
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Ingår i: Proceedings of the 103rd Transportation Research Board Annual Meeting.
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Konferensbidrag (refereegranskat)abstract
- Efficient traffic management requires an understanding of mobility patterns in the road network, where one important component is route choice. This study aims to analyze how route choice models can be adapted to efficient urban traffic management and intelligent transport systems (ITS), by constructing route sets and attributes from GPS and network data. With a route choice model that is responsive to traveltime changes in the network, travel behavior during incidents can be predicted to evaluate traffic management policies, such as traveler information and traffic control. The dataset consists of about 400,000 vehicle trips and is divided into a training dataset and a test dataset. The two datasets are compared, and the experiments show that the routes used are similar. Discrete route choice models are estimated with one data-driven path identification approach (DDPI) and one where the data-driven path set is augmented with routes from a network-based shortest path generation with link penalty (NBPA). The result suggests that the traveltime has a larger impact on the route choice when the model is trained on the NBPA route set and that the route's simplicity, length, and traveltime are important attributes for the route choice, which are useful insights in a traffic management context.
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| 18. |
- Danielsson, Anna, 1995-
(författare)
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Towards efficient urban road transport using multimodal traffic management
- 2024
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- As travel demand and urbanization increase, they cause road con-gestion. This results in lost productivity, reduced accessibility, and negative effects on the environment. Solutions to reduce congestion in the transport network include urban traffic management. It could for example be regulating signal control, variable speed limit, and ramp metering, or distributing traveler information about traveltimes and congestion through radio broadcasts, variable message signs, or navigation apps. A multimodal traffic management system utilizes several transportation modes within an integrated system to improve network performance and robustness. Large-scale mobility data from both the public transport network and private vehicles enable a better understanding of multimodal travel patterns. Traffic data can also be used to estimate reliable traffic models that can support evaluation and prioritization of traffic management measures. The aim of the thesis is to identify synergies and challenges of multimodal traffic management. The aim includes analyzing, devel-oping, and evaluating dynamic route choice models that can support multimodal traffic management decisions, using large-scale passive mobility data. First, recent trends are explored in the transition to more efficient road transport, emphasizing the role of monitoring and modeling traffic. Second, related literature is surveyed to identify the potential synergies and challenges of multimodal traffic management. Requirements of data and models in a decision support system that can help to prioritize between multimodal traffic management measures are also identified. Based on these requirements, route choice in the road network is analyzed using GPS trajectory data. This provides insights into how data-driven route choice models can be a component in multimodal traffic management. The thesis contributes to the understanding of how a decision support system for multimodal traffic management can be developed, how route choice modeling can be used in such a tool, and how multimodal traffic management is needed in the transition towards more efficient road transport.
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| 19. |
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| 20. |
- Fredriksson, Anna, 1979-, et al.
(författare)
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Construction related urban disturbances : Identification and linking with an IoT-model
- 2022
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Ingår i: Automation in Construction. - : Elsevier. - 0926-5805 .- 1872-7891. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- While being a significant part of the urban development, construction projects disturb different stakeholders in various ways. There are three problems associated with construction disturbances: (i) most of these disturbances are not recognised by the people causing them, (ii) they are not monitored and (iii) if they are to be monitored, data is spread among stakeholders. This paper defines what a disturbance is, presents a list of disturbances, linking disturbances to stakeholders and, categorising them based on their distance from construction sites (responding to (i)). Next, a IoT domain model is developed, demonstrating how IoT in construction needs to be combined with the sensors of smart cities to capture the primitives of these disturbances (responding to (iii)). This is a first step towards enabling large-scale data-gathering of construction transport disturbances (responding to (ii)), which is a necessity to predict them and allow better construction transport planning to decrease disturbances.
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| 21. |
- Fredriksson, Anna, 1979-, et al.
(författare)
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Störningsfri stad : slutrapport i projektet Visualiserad byggtrafikplanering för en störningsfri stadsutveckling
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Störningsfri stad har kombinerat kunskaper inom Trafikplanering, Visualisering, Bygglogistik, Sensorer och Offentlig planering och styrning. Projektet har letts av Linköpings universitet, Institutionen för Teknik och Naturvetenskap och finansierats av Vinnova, IHS. Projektet har löpt mellan slutet av 2018 och 2021 ut. Projektdeltagare har varit VTI, RISE, Norrköpings kommun, Linköpings kommun, Stockholm stad, Uppsala kommun, Trafikverket Projekt Ostlänken, LE Lundbergs Fastigheter, Wiklunds Åkeri, Wellsec, SanktKors, Byggföretagen, Telenor och Logistikia.Projektet har utvecklat en verktygsprototyp som stöttar kollaborativ planering av byggtrafik och stadsplanering genom att visualisera pågående byggprojekts sammanlagda mängd transporter och var i staden (i form av en kartvy) det uppstår störningar i form av förseningar pga dessa. Verktyget bygger på en MATSim trafikmodell (i nuläget Norrköping) inkluderande både persontransporter (modellerat baserat på mobilnätsdata) och byggtrafik (modellerat baserat på data från bygglogistiklösningar). Med hjälp av verktyget kan olika scenarier för att minska störningarna av byggtransporter testas. För att stötta användandet av verktyget har en kollaborativ planeringsprocess som visar på hur de olika aktörerna involverade i planeringen av byggtransporter och stadsutveckling behöver interagera med varandra utvecklats. Projektet också deltagit i utvecklingen av en sensorbox (partiklar, luftfuktighet, temperatur och ljud) samt slangmätningsmetodik för att öka kunskapen om byggtransporter. Baserat på de resultat som projektet har behovsägarna har påbörjat arbeten med att bättre hantera de störningar som uppstår pga byggprojekt i staden.
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| 22. |
- Grumert, Ellen, 1983-, et al.
(författare)
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Effects of incidents on motorways : a proposed methodology for estimating and predicting demand, duration and capacity for incident management
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Effective traffic incident management is important to minimize negative impacts of congestion caused by incidents. Predictions of the traffic state at the incident site and its surrounding road network, together with an estimate of incident duration, can be used to get increased knowledge about current and future incident characteristics. The aim is to propose methods for estimating capacity, duration and demand profiles in case of an incident, and to explore how the level of detail and the possibility to identify explanatory variables for incidents with similar characteristics given currently available data sources affects the proposed methods. The knowledge obtained within the project is intended to be used for incident management. The report presents a methodology for predicting capacity, traffic demand, and incident duration, when none of the parameters are known. The proposed methods can be used as input to traffic models, when the purpose is to perform scenario-based analysis and real-time predictions to be used in the decision-making processes for traffic management/control, but also for predicting travel times which can be communicated to road users.A motorway use-case study area south of Stockholm is used to propose methods for predicting incident duration, capacity and demand profiles based on the availability of data. The methodology is evaluated by using the predicted variables as input in a scenario-based analysis with two queue models.
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| 23. |
- Grumert, Ellen, 1983-, et al.
(författare)
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Förslag på metodik för systematisk utvärdering av ITS i motorvägsmiljö : en sensorbaserad ansats
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten är en av två rapporter som beskriver resultatet från projektet Utvärdering av förbättrad motorvägsstyrning – en fallstudie. Projektet har som syfte att ta fram en metodik för att utvärdera före- och efterstudier för ITS-åtgärder (Intelligenta Transport Systems-åtgärder) i motorvägsmiljö och applicera metodiken på en teststräcka på E4 vid Södertälje för att utvärdera tillämpbarheten av metoden samt effekter på framkomlighet, säkerhet och miljö. När man vill studera förändringar på grund av ITS-åtgärder på vägsträckor med tätt belägna sensorer finns goda möjligheter till före- och eftermätningar. I dagsläget saknas ofta sådana studier och det finns därmed begränsat med kunskap om hur sådana före-efterstudier bäst ska genomföras. Syftet med denna rapport är att ta fram ett förslag på utvärderingsmetodik med avseende på framkomlighet, trafiksäkerhet och miljö då tillgången på data från tätt belägna sensorer är god. I rapporten föreslås välgrundade metoder för att på ett rättvist sätt kunna jämföra före- och eftersituationen med varandra. En viktig aspekt är att identifiera dagar med likartade trafikförhållanden för att undvika att dagar med olika trafiksituationer och därmed i praktiken icke-jämförbara dagar ställs mot varandra vid utvärderingen av effekterna av ITS-åtgärden. Ytterligare en rapport presenterar resultaten från utvärderingen på teststräckan vid Södertälje.
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| 24. |
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| 25. |
- Grumert, Ellen, 1983-, et al.
(författare)
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Utvärdering av styrning med variabla hastighetsgränser med fokus på framkomlighet : en fallstudie på E4 vid Södertälje
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten är en av två rapporter som beskriver resultatet från det Trafikverksfinansierade projektet Utvärdering av förbättrad motorvägsstyrning – en fallstudie. Projektet har som syfte att ta fram en metodik för att utvärdera före-efterstudier för ITS-åtgärder (Intelligenta Transport Systems-åtgärder) i motorvägsmiljö och applicera metodiken på en teststräcka på E4 vid Södertälje för att utvärdera tillämpbarheten av metoden samt effekter på framkomlighet, säkerhet och miljö. När man vill studera förändringar på grund av ITS-åtgärder på vägsträckor med tätt belägna sensorer finns goda möjligheter till före- och eftermätningar. I dagsläget saknas ofta sådana studier och det finns därmed begränsat med kunskap om hur sådana före-efterstudier bäst ska genomföras. Syftet med denna rapport är att applicera den metodik som har tagits fram i projektet och utvärdera effekter på framkomlighet, trafiksäkerhet och miljö för en fallstudie vid Södertälje. På sträckan har en ny styrstrategi för val av variabla hastighetsgränser implementerats. På teststräckan har det funnits tätt belägna detektorer, installerade på 150–300 meters avstånd, i många år. Eftersom det redan innan ny styrstrategi fanns på plats gavs goda möjligheter att mäta trafikförhållandena på teststräckan, ges ett unikt tillfälle att jämföra trafikförhållanden före och efter styrstrategin är implementerad. Resultaten från utvärderingen bidrar, utöver att utvärdera tillämpbarheten av metodiken, till kunskap om hur före[1]efterstudier bör designas och variabla hastighetsgränsers inverkan på trafiksituationen då målet är att förbättra trafikförhållanden vid framkomlighetsproblem.
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| 26. |
- Grumert, Ellen, 1983-, et al.
(författare)
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Variabla hastighetsgränser för Stockholms motorvägsnät : effekter av alternativa algoritmer och möjligheter till styrning genom estimerade trafiktillstånd
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Variabla hastighetsgränser är väl utbrett på Stockholms stadsnära motorvägar och en del av Stockholms Motorway Control System (MCS). Målet med dagens system är att minska risken för olyckor och följdolyckor vid låga hastigheter, trafikstockningar m.m. Detta görs genom att mäta medelhastigheten med hjälp av fasta detektorer och uppdatera hastigheten som visas på variabla meddelandeskyltar utifrån rådande trafiktillstånd. I och med att efterfrågan på resor i Stockholm under rusningstid överstiger den tillgängliga kapaciteten i vägnätet är behovet av ett effektivt trafiksystem stort. Variabla hastighetsgränser kan bidra till ökad framkomlighet, men då dagens system har som målsättning att öka säkerheten är effekter som leder till ökad framkomlighet begränsade. Dessutom finns det i dagens system ett stort beroende av fungerande detektorer som mäter trafiktillståndet så korrekt som möjligt för att valet av hastighet ska kunna bestämmas på ett effektivt sätt.Syftet med den här rapporten är att undersöka alternativa styralgoritmer för att bestämma variabla hastighetsgränser på Stockholms motorvägsnät. Målet är att öka framkomligheten jämfört med dagens system. Två olika sträckor med olika komplexitet, trafiksituation och problematik studeras. Valet av studerade styralgoritmer för de olika sträckorna väljs för att på bästa sätt motverka den problematiken som uppstår på de specifika sträckorna. Därmed kan val av algoritmer komma att skilja sig åt beroende på sträcka. I projektet utvärderas också om estimering av trafiktillståndet kan användas för att förbättra informationsflödet till algoritmerna då detektorer inte fungerar som de ska eller helt saknas, vilket i sin tur kan leda till förbättrad anpassning av de variabla hastighetsgränserna. Detta görs av för en av de studerade sträckorna. Styralgoritmerna utvärderas med mikroskopisk trafiksimulering och metoden utvecklad i projektet Mobile Millenium Stockholm (MMS), som bygger på en makroskopisk trafikflödesmodell och Kalman filtrering, används för estimering av trafiktillståndet.
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| 27. |
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| 28. |
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| 29. |
- Gundlegård, David, 1978-, et al.
(författare)
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Generating Road Traffic Information from Cellular Networks - New Possibilities in UMTS
- 2006
-
Ingår i: Proceedings 2006 6th International Conference onITS Telecommunications. - 0780395875 - 0780395875 ; , s. 1128-1133
-
Konferensbidrag (refereegranskat)abstract
- This paper summarizes different approaches to collecting road traffic information from second-generation cellular systems (GSM) and point out the possibilities that arise when third generation systems (UMTS) are used. Cell breathing is a potential problem, but smaller cells, soft handover and flexible measurements have the potential to increase the usage area and information quality when road traffic information is extracted from the UMTS network compared to using the GSM network
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| 30. |
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| 31. |
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| 32. |
- Gundlegård, David, 1978-, et al.
(författare)
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The Smartphone as Enabler for Road Traffic Information Based on Cellular Network Signalling
- 2012
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The higher penetration rate of GPS-enabled smartphones together with their improved processing power and battery life makes them suitable for a nu mber of participatory sensing applications. The purpose of this paper is to an alyse how GPS-enabled smartphones can be used in a participatory sensingcontext to build a radio map for RSS-based positioning, with a special focus on road traffic information based on cellular network signalling.The CEP-67 location accuracy achieved is 75 meters for both GSM and UMTS using Bayesian classification. For this test site, the accuracy is similar for GSM and UMTS, with slightly better results for UMTS in the CEP-95 error metric.The location accuracy achieved is good enough to avoid large errors in travel time estimation for highway environments, especially considering the possibility to filter out estimates with low accuracy using for example the posterior bin probability in Bayesian classification. For urban environments more research is required to determine how the location accuracy will affect the path inference problem in a dense road network. The location accuracy achieved in this paper is also sufficient for other traffic information types, for example origin-destination estimation based on location area updates.
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| 33. |
- Gundlegård, David, 1978-, et al.
(författare)
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The Smartphone As Enabler for Road Traffic Information Based on Cellular Network Signalling
- 2013
-
Ingår i: Intelligent Transportation Systems (ITSC), 2013. - : IEEE. - 9781479929146 ; , s. 2106-2112
-
Konferensbidrag (refereegranskat)abstract
- The higher penetration rate of GPS-enabled smartphones together with their improved processing power and battery life makes them suitable for a number of participatory sensing applications. The purpose of this paper is to analyse how GPS-enabled smartphones can be used in a participatory sensing context to build a radio map for RSS-based positioning, with a special focus on road traffic information based on cellular network signalling. The CEP-67 location accuracy achieved is 75 meters for both GSM and UMTS using Bayesian classification. For this test site, the accuracy is similar for GSM and UMTS, with slightly better results for UMTS in the CEP-95 error metric. The location accuracy achieved is good enough to avoid large errors in travel time estimation for highway environments, especially considering the possibility to filter out estimates with low accuracy using for example the posterior bin probability in Bayesian classification. For urban environments more research is required to determine how the location accuracy will affect the path inference problem in a dense road network. The location accuracy achieved in this paper is also sufficient for other traffic information types, for example origin-destination estimation based on location area updates.
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| 34. |
- Gundlegård, David, 1978-
(författare)
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Transport Analytics Based on Cellular Network Signalling Data
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cellular networks of today generate a massive amount of signalling data. A large part of this signalling is generated to handle the mobility of subscribers and contains location information that can be used to fundamentally change our understanding of mobility patterns. However, the location data available from standard interfaces in cellular networks is very sparse and an important research question is how this data can be processed in order to efficiently use it for traffic state estimation and traffic planning.In this thesis, the potentials and limitations of using this signalling data in the context of estimating the road network traffic state and understanding mobility patterns is analyzed. The thesis describes in detail the location data that is available from signalling messages in GSM, GPRS and UMTS networks, both when terminals are in idle mode and when engaged in a telephone call or a data session. The potential is evaluated empirically using signalling data and measurements generated by standard cellular phones. The data used for analysis of location estimation and route classification accuracy (Paper I-IV in the thesis) is collected using dedicated hardware and software for cellular network analysis as well as tailor-made Android applications. For evaluation of more advanced methods for travel time estimation, data from GPS devices located in Taxis is used in combination with data from fixed radar sensors observing point speed and flow on the road network (Paper V). To evaluate the potential in using cellular network signalling data for analysis of mobility patterns and transport planning, real data provided by a cellular network operator is used (Paper VI).The signalling data available in all three types of networks is useful to estimate several types of traffic data that can be used for traffic state estimation as well as traffic planning. However, the resolution in time and space largely depends on which type of data that is extracted from the network, which type of network that is used and how it is processed.The thesis proposes new methods based on integrated filtering and classification as well as data assimilation and fusion that allows measurement reports from the cellular network to be used for efficient route classification and estimation of travel times. The thesis also shows that participatory sensing based on GPS equipped smartphones is useful in estimating radio maps for fingerprint-based positioning as well as estimating mobility models for use in filtering of course trajectory data from cellular networks.For travel time estimation, it is shown that the CEP-67 location accuracy based on the proposed methods can be improved from 111 meters to 38 meters compared to standard fingerprinting methods. For route classification, it is shown that the problem can be solved efficiently for highway environments using basic classification methods. For urban environments the link precision and recall is improved from 0.5 and 0.7 for standard fingerprinting to 0.83 and 0.92 for the proposed method based on particle filtering with integrity monitoring and Hidden Markov Models.Furthermore, a processing pipeline for data driven network assignment is proposed for billing data to be used when inferring mobility patterns used for traffic planning in terms of OD matrices, route choice and coarse travel times. The results of the large-scale data set highlight the importance of the underlying processing pipeline for this type of analysis. However, they also show very good potential in using large data sets for identifying needs of infrastructure investment by filtering out relevant data over large time periods.
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| 35. |
- Gundlegård, David, 1978-, et al.
(författare)
-
Travel demand analysis with differential private releases
- 2015
-
Ingår i: Netmob 2015.
-
Konferensbidrag (refereegranskat)abstract
- The use of mobile phone data for planning of transport infrastructure has been shown to have great potential in providing a means of analyzing the efficiency of a transportation system and assisting in the formulation of transport models to predict its future use. In this paper we describe how this type of data can be processed and used in order to act as both enablers for traditional transportation analysis models, and provide new ways of estimating travel behavior. Specifically, we propose a technique for describing the travel demand by constructing time sliced origin destination matrices which respect the level of detail available in Call Detail Records (CDR) from mobile phone use.When analyzing large quantities of human mobility traces, the aspects of sensitivity of traces to be analyzed, and the scale at which such analysis can be accounted for is of high importance. The sensitivity implies that identifiable information must not be inferred from the data or any analysis of it. Thus, prompting the importance of maintaining privacy during or post-analysis stages. We aggregate the raw data with the goal to retain relevant information while at the same time discard sensitive user specifics, through site sequence clustering and frequent sequence extraction. These techniques have at least three benefits: data reduction, information mining, and anonymization. Further, the paper reviews the aggregation techniques with regard to privacy in a post-processing step.The approaches presented in the paper for estimation of travel demand and route choices, and the additional privacy analysis, build a comprehensive framework usable in the processing of mobile phone data for transportation planning.The project presented in this paper a part of the D4D-Senegal challenge.
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| 36. |
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| 37. |
- Stenberg, Rebecca, 1957-, et al.
(författare)
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Lokalisering i oländig terräng : Slutrapport Terrängpejlen-projektet
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Flygplan och personer som råkar i nöd i oländig terräng kan använda nödsändare som via satellitsystemet COSPAS-SARSAT kan meddela en räddningscentral att det är ett nödläge, samt ungefärlig position. För att sedan lokalisera nödsändaren används ofta flygande resurser, till exempel helikopter, med fast pejl-utrustning som kan fastställa riktningen mot signalkällan. Ibland kan dock flygande resurser inte användas, som till exempel vid dåligt väder eller om de är upptagna på annat uppdrag, och i dagsläget finns inget bra markbaserat alternativ. Syftet med projektet Terrängpejlen var därför att utveckla och utvärdera ett system för markbaserade pejlresurser, så kallad handpejl. Följande slutsatser kunde dras från projektet:Handpejl kommer att behövas mycket sällan vid skarpa insatser. En analys av de senaste fem årens relevanta incidenter tyder på att handpejl inte hade varit till nytta vid något tillfälle. Detta kan dock komma att ändras till exempel. som en följd av ökad frekvens av extremväder, eller vid höjd beredskap på grund av militära hot.Det finns i dag ingen pejl som är perfekt för ändamålet att lokalisera nödsändare. Av de tre pejlar som testades i projektet bedömdes två kunna uppfylla grundfunktionen, att hitta en nödsändare, men hade brister i till exempel användarvänlighet. Bäst för ändamålet bedömdes Rhotheta RT 400 vara, medan Rohde & Schwarz PR 200 är att föredra om pejlen också ska användas för att hitta störsändare, vilket kan vara önskvärt om den är stationerad på en flygplats.Pejling kan utföras av räddningstjänstpersonal på utvalda flygplatser i samverkan med fjällräddare som får agera transportörer. Vid flera flygplatser finns det fortfarande kvar pejlutrustning, trots slopat krav på detta, och det finns också intresse av att upprätthålla kunskapen.Utlarmning och kommunikation bör ske enligt dagens rutin med regelbundna samverkanskonferenser. Direkta kontaktvägar mellan pejloperatörer (flygplatspersonal) och transportörer (fjällräddare) måste upprättas och samverkan måste övas regelbundet.Nödvändig utbildning och övning omfattar utbildning av lokala instruktörer, lokal operatörsutbildning samt regelbundna samverkansövningar. Instruktörsutbildning kan genomföras av Sjöfartsverket. Instruktörerna sköter sedan lokala utbildningar och övningar, vilka bör genomföras minst en gång per år. Dessa kan kombineras med återkommande samverkansövningar tillsammans med Sjö- och flygräddningscentralen, Polisen, SOS Alarm och Fjällräddningen.Sjöfartsverket bör vara ansvarig organisation som äger pejlarna och lånar ut dessa till flygplatserna, samt har ansvar för tillsyn av verksamheten. Urval av flygplatser bör göras i första hand med utgångspunkt från geografiskt täckningsområde. Utslaget på årsbasis blir den dominerande kostnaden vid en implementering att ha flygplatspersonal i beredskap. Med ett riktpris på 250 000 SEK per pejl, blir det också en viss investeringskostnad om många flygplatser ska utrustas.
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| 38. |
- Tsanakas, Nikolaos, 1987-
(författare)
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Data-Driven Approaches for Traffic State and Emission Estimation
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traffic congestion is one of the most severe problems in modern urban areas. Besides the amplified travel times, traffic congestion intensifies the amount of emitted pollutants impacting human health and the environment. By making the appropriate interventions in traffic, transportation planners can mitigate congestion and enhance the performance of a traffic system. One crucial step in traffic planning and management is the estimation of the current or historical traffic state of a network. The estimation of the traffic state variables (traffic flow, density and speed) reveals the problematic parts of a network, namely, the parts associated with severe congestion and high emission rates. Traffic-related observations and traffic models constitute two core elements of a traffic state estimation approach. While the available observation data explicitly or implicitly provide partial information on the traffic state, traffic models define the traffic behaviour and contribute to estimating the variables when they are not directly observable. The estimated traffic state variables form the input to the so-called emission models, which estimate the mass of the emitted pollutants.The type and availability level of the observation data play a key role in traffic state and emission estimation. Traditionally, the primary source of traffic-related field data are stationary detectors (loop detectors, radar sensors or cameras). Today, following the late advances in communication systems, a vast amount of traffic-related data from mobile sources (GPS or cellular networks) is available. Such high data availability may give transportation planners new insights into understanding traffic behaviour. Appropriate exploitation of data coming from mobile sources can improve the existing approaches for estimating the traffic state and emissions.The broad aim of this thesis is to enhance the quality of traffic state and emission estimation. A special focus is given to the development of methods for exploiting the growing availability of traffic-related field data. By combining traffic data and models, the thesis proposes data-driven approaches for traffic state and emission estimation.The first part of the thesis (Paper I and Paper II) focuses on improving the current approaches for network-wide emission estimation. Traditionally, network-wide emission estimations rely on a static traffic-modelling framework. In Paper I, we suggest an alternative emission estimation approach, which is based on a quasi-dynamic traffic model. To evaluate our approach, we perform field experiments on a 19 km long highway stretch in Stockholm. The results show that our method can improve the spatiotemporal distribution of the estimated emissions. In Paper II, the approach suggested in Paper I is applied to a more extensive network covering the city of Norrköping. The results indicate that our approach yields a realistic spatial layout of emissions.The second part of the thesis (Paper III and Paper IV) suggests novel data-driven approaches for estimating network-wide traffic flows and demand. More specifically, in Paper III, we develop a data-driven traffic-flow propagation approach by utilising traveltime observations. Our method is based on a piecewise linear approximation of the travel time function, which allows the use of an efficient event-based structure for propagating the traffic flow. We evaluate our approach through simulation-based experiments, and the results provide proof of the concept. In Paper IV, we exploit the approach suggested in Paper III to develop an efficient data-driven scheme for estimating the traffic demand. The results of the simulation-based experiments indicate that our approach might lead to more accurate estimations compared to other data-driven estimation approaches suggested in the literature.Finally, the last part of the thesis (Paper V) focuses on the estimation of fuel consumption and emissions at a vehicle level. In paper V, we propose a novel method for generating virtual vehicle trajectories by fusing data from different sources. Our approach provides a detailed description of vehicle kinematics, and thus, it permits the use of the underlying virtual vehicle trajectories to vehicle dynamics-sensitive applications, such as emission modelling. The results of our experiments show that the advanced modelling of vehicle kinematics can enhance the accuracy of the estimated emissions.
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