Ellen Grumert - Academia.edu (original) (raw)

Papers by Ellen Grumert

Journal of Transportation Engineering, Part A: Systems

IEEE Transactions on Intelligent Transportation Systems

Effective traffic incident management is important to minimize negative impacts of congestion cau... more 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 analysi...

Publication of: Swedish National Road and Transport Research Institute, 2021

A literature survey has been conducted regarding international traffic calming measures that coul... more A literature survey has been conducted regarding international traffic calming measures that could have a potential use in Sweden and other Nordic countries. Focus has been on measures in new traffic environments and ITS (Intelligent Transport System) based solutions. Information has been obtained through searches in literature databases and on different homepages, as well as from contacts in networks. Initially, we describe common traffic calming measures used today in Swedish traffic environments. For example, different forms of vertical and horizontal measures, and different types of surfaces, road markings and paintings. In the case of existing ITS solutions, we mention speed reminder signs, variable message signs and Motorway Control System (MCS). New kinds of physical measures that have most potential for use are e.g. modifications of speed bumps and the construction of small curves that enforce lower speed. Such curvatures can be used at entrances to communities or before rou...

Trafikverket arbetar kontinuerligt med att förbättra dagens motorvägsstyrningssystem i svenska st... more Trafikverket arbetar kontinuerligt med att förbättra dagens motorvägsstyrningssystem i svenska storstäder. Under 2018–2020 pågår arbetet med att öka flexibiliteten kring val av variabel hastighetsgräns i existerande motorvägsstyrningssystem. Önskvärt är att styrstrategierna för val av variabel hastighetsgräns i större utsträckning är platsspecifika och beroende av infrastruktur och trafiksituationen på platsen. Målet med styrstrategierna bör kunna vara både trafiksäkerhet och framkomligheten. Ett viktigt krav är att styrstrategierna ska kunna skrivas som en trafikföreskrift för att möjliggöra tvingande hastighetsgränser (röd ring), istället för rekommenderade hastigheter som används frekvent idag. Denna studie bidrar till Trafikverkets arbete med att förbättra trafikstyrningen på svenska stadsnära motorvägar genom att ge forsknings och evidensbaserat stöd till hur en styrstrategi bör utformas. Hänsyn tas till att styrstrategin ska kunna utformas som en föreskrift och samtidigt uppn...

Transportation Research Board Annual Meeting, 2019

Connected vehicles can be used in two ways in traffic signal control: (1) as a complement to, or ... more Connected vehicles can be used in two ways in traffic signal control: (1) as a complement to, or for removing of, stationary detectors and to give more detailed information about position, speed, etc. of individual vehicles with the goal to optimize the traffic signal control strategy or (2) to receive information about the traffic signal status for optimization of the connected vehicles movements when traversing the intersection or for optimization of the traffic system. In Sweden, a traffic actuated control strategy is commonly used, where the traffic signal status is adjusted based on detection of individual vehicles. It is today unclear if connected vehicles can be used in the current Swedish traffic signal control settings or if the control strategy must be adapted to better take advantage of connected vehicle information. The purpose with this report is to investigate how, and if, connected vehicles can be incorporated in the current Swedish traffic signals when the goal is to...

Variabla hastighetsgränser är väl utbrett på Stockholms stadsnära motorvägar och en del av Stockh... more 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 ...

Capacity estimation at bottleneck locations along urban motorways are of importance for control p... more Capacity estimation at bottleneck locations along urban motorways are of importance for control purposes. If the capacity is known, the control strategy can be designed to not exceed capacity, or at least prolong the time until exceeding the capacity and thereby entering congested traffic conditions. In this study we show how the probability distribution of capacity can be estimated using automatic identification of traffic breakdowns and clustering methods. c © 2020 Peer-review under responsibility of the scientific committee of the 23rd EURO Working Group on Transportation Meeting.

Variabla hastighetsgranser ar val utbrett pa Stockholms stadsnara motorvagar och en del av Stockh... more Variabla hastighetsgranser ar val utbrett pa Stockholms stadsnara motorvagar och en del av Stockholms Motorway Control System (MCS). Malet med dagens system ar att minska risken for olyckor och fol ...

Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute o... more Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute of Transportation Systems“. We are publishing in this series fascinating, scientific topics from the Institute of Transportation Systems of the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt e.V. - DLR) and from his environment. We are providing libraries with a part of the circulation. Outstanding scientific contributions and dissertations are here published as well as projects reports and proceedings of conferences in our house with different contributors from science, economy and politics. With this series we are pursuing the objective to enable a broad access to scientific works and results. We are using the series as well as to promote practically young researchers by the publication of the dissertation of our staff and external doctoral candidates, too. Publications are important milestones on the academic career path. With the series „Reports of the DLR-Institut...

Smart cities, participatory sensing as well as location data available in communication systems a... more Smart cities, participatory sensing as well as location data available in communication systems and social networks generates a vast amount of heterogeneous mobility data that can be used for traffic management. This chapter gives an overview of the different data sources and their characteristics and describes a framework for utilizing the various sources efficiently in the context of traffic management. Furthermore, different types of traffic models and algorithms are related to both the different data sources as well as some key functionalities of active traffic management, for example short-term prediction and control.

As the world population and the traffic demand are constantly inflating, there is a substantial n... more As the world population and the traffic demand are constantly inflating, there is a substantial need to procure a safe and effective method for traffic control and management. Thus, traffic signals operate to manage the flow of vehicles and vulnerable road users through intersections. Intelligent Transport Systems (ITS) technologies based on vehicle connectivity and information exchange may overcome the cons of fixed‐time traffic signals in coping with the unplanned traffic stream. The roadmap for operating connected vehicles in an urban environment is still in the planning phase and in order to achieve sustainable results, a proper management technique must control the flow of vehicles. Green Light Optimal Speed Advisory (GLOSA) utilizes infrastructure and vehicles communication through using current signal plan settings and updated vehicular information in order to influence the intersection approach speeds. This thesis presents a traffic microsimulation study that investigates th...

Variable Speed Limit Systems (VSLS) where gantries are showing speed limits based on, for example... more Variable Speed Limit Systems (VSLS) where gantries are showing speed limits based on, for example, traffic volume or other road or traffic conditions exists on motorways in many countries. The aim ...

Control algorithms used for deciding on the speed limits in variable speed limit systems are cruc... more Control algorithms used for deciding on the speed limits in variable speed limit systems are crucial for the performance of the system. Today, many of the control algorithms used are based on fixed thresholds in speed and/or flow for changing the speed limit. The algorithms are not necessarily reflecting the conditions on the road, which might lead to low traffic efficiency. The authors hypothesis is that by use of a simple and efficient control algorithm that is better in reflecting the conditions on the road, both traffic efficiency and traffic safety could be increased. In this study, four control algorithms used in variable speed limit systems, and fulfilling the above criteria, are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the design of, and the objective with, the control algorithm have impact on the performance. Moreover, the time needed ...

European Transport Research Review

The control algorithm used for deciding on the speed limit in variable speed limit systems is cru... more The control algorithm used for deciding on the speed limit in variable speed limit systems is crucial for the performance of the systems. The algorithm is designed to fulfil the purpose of the variable speed limit system, which can be one or several of the following aspects: increasing safety, increasing efficiency and decreasing environmental impacts. Today, many of the control algorithms used in practice are based on fixed thresholds in speed and/or flow. Therefore, they are not necessarily reflecting the current traffic conditions. Control algorithms with a greater level of complexity can be found in the literature. In this paper, four existing control algorithms are investigated to conclude on important characteristics affecting the performance of the variable speed limit system. The purpose of the variable speed limit system and, consequently, the design of the control algorithm differ. Requirements of the investigated control algorithms are that they should be easy to interpret and the execution time should be short. The algorithms are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the characteristics of the variable speed limit system and the design of the control algorithm will have effect on the resulting traffic performance, given that the drivers comply with the variable speed limits. Moreover, the time needed to trigger the system, the duration and the size of speed limit reductions, and the location of the congestion are factors of importance for the performance of variable speed limit systems.

Transportation Research Procedia

Motorway tra c management systems are useful for improving the tra c conditions on urban motorway... more Motorway tra c management systems are useful for improving the tra c conditions on urban motorways. One of the most common motorway tra c management systems are variable speed limit systems. ese systems adapt the speed limits based on the prevailing tra c conditions measured by roadside detectors and recommended or compulsory speed limits are shown on variable message signs installed on gantries over the road. e systems consist of three parts; the control algorithm used to determine which speed limit to be displayed, a method for estimating the tra c conditions to be used as input for the control algorithm and the infrastructure for application of the variable speed limits. e goal of the systems is o en to increase safety or e ciency. Recent development in the eld of connected vehicles have opened up for a new type of data source, as the status of a connected vehicle and its surroundings can be communicated at arbitrary locations. Hence, by the use of connected vehicles in variable speed limit systems there is a potential of reducing the amount of roadside equipment. It is even possible to control the connected vehicles towards the current speed limit without the use of variable message signs. is allows for the application of variable speed limits at arbitrary locations. e aim of this thesis is to examine how connected vehicles can be used to improve the e ciency of variable speed limit systems. e thesis contribute with new and improved methods using connected vehicles in all three parts of a variable speed limit system. e suggested methods are evaluated by microscopic tra c simulation. e overall iii vii Johansson, it has been a true privilege to share my PhD time with you both as a friend and as a support to my research and the ups and downs coming with it. Henric Jonsson, you have become a good friend and a source to renewed energy at work. You are truly missed at KTS. To my family and friends, thank you for always being there, for your endless support and your love. To my beloved Tobbe, I couldn't have done it without you. ank you for always believing in me. Saga and Emil, I am so thankful for all your love and joy always giving me the strength to keep going.

Journal of Transportation Engineering, Part A: Systems

IEEE Transactions on Intelligent Transportation Systems

Effective traffic incident management is important to minimize negative impacts of congestion cau... more 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 analysi...

Publication of: Swedish National Road and Transport Research Institute, 2021

A literature survey has been conducted regarding international traffic calming measures that coul... more A literature survey has been conducted regarding international traffic calming measures that could have a potential use in Sweden and other Nordic countries. Focus has been on measures in new traffic environments and ITS (Intelligent Transport System) based solutions. Information has been obtained through searches in literature databases and on different homepages, as well as from contacts in networks. Initially, we describe common traffic calming measures used today in Swedish traffic environments. For example, different forms of vertical and horizontal measures, and different types of surfaces, road markings and paintings. In the case of existing ITS solutions, we mention speed reminder signs, variable message signs and Motorway Control System (MCS). New kinds of physical measures that have most potential for use are e.g. modifications of speed bumps and the construction of small curves that enforce lower speed. Such curvatures can be used at entrances to communities or before rou...

Trafikverket arbetar kontinuerligt med att förbättra dagens motorvägsstyrningssystem i svenska st... more Trafikverket arbetar kontinuerligt med att förbättra dagens motorvägsstyrningssystem i svenska storstäder. Under 2018–2020 pågår arbetet med att öka flexibiliteten kring val av variabel hastighetsgräns i existerande motorvägsstyrningssystem. Önskvärt är att styrstrategierna för val av variabel hastighetsgräns i större utsträckning är platsspecifika och beroende av infrastruktur och trafiksituationen på platsen. Målet med styrstrategierna bör kunna vara både trafiksäkerhet och framkomligheten. Ett viktigt krav är att styrstrategierna ska kunna skrivas som en trafikföreskrift för att möjliggöra tvingande hastighetsgränser (röd ring), istället för rekommenderade hastigheter som används frekvent idag. Denna studie bidrar till Trafikverkets arbete med att förbättra trafikstyrningen på svenska stadsnära motorvägar genom att ge forsknings och evidensbaserat stöd till hur en styrstrategi bör utformas. Hänsyn tas till att styrstrategin ska kunna utformas som en föreskrift och samtidigt uppn...

Transportation Research Board Annual Meeting, 2019

Connected vehicles can be used in two ways in traffic signal control: (1) as a complement to, or ... more Connected vehicles can be used in two ways in traffic signal control: (1) as a complement to, or for removing of, stationary detectors and to give more detailed information about position, speed, etc. of individual vehicles with the goal to optimize the traffic signal control strategy or (2) to receive information about the traffic signal status for optimization of the connected vehicles movements when traversing the intersection or for optimization of the traffic system. In Sweden, a traffic actuated control strategy is commonly used, where the traffic signal status is adjusted based on detection of individual vehicles. It is today unclear if connected vehicles can be used in the current Swedish traffic signal control settings or if the control strategy must be adapted to better take advantage of connected vehicle information. The purpose with this report is to investigate how, and if, connected vehicles can be incorporated in the current Swedish traffic signals when the goal is to...

Variabla hastighetsgränser är väl utbrett på Stockholms stadsnära motorvägar och en del av Stockh... more 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 ...

Capacity estimation at bottleneck locations along urban motorways are of importance for control p... more Capacity estimation at bottleneck locations along urban motorways are of importance for control purposes. If the capacity is known, the control strategy can be designed to not exceed capacity, or at least prolong the time until exceeding the capacity and thereby entering congested traffic conditions. In this study we show how the probability distribution of capacity can be estimated using automatic identification of traffic breakdowns and clustering methods. c © 2020 Peer-review under responsibility of the scientific committee of the 23rd EURO Working Group on Transportation Meeting.

Variabla hastighetsgranser ar val utbrett pa Stockholms stadsnara motorvagar och en del av Stockh... more Variabla hastighetsgranser ar val utbrett pa Stockholms stadsnara motorvagar och en del av Stockholms Motorway Control System (MCS). Malet med dagens system ar att minska risken for olyckor och fol ...

Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute o... more Dear reader, You are holding in your hands a volume of the series „Reports of the DLR-Institute of Transportation Systems“. We are publishing in this series fascinating, scientific topics from the Institute of Transportation Systems of the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt e.V. - DLR) and from his environment. We are providing libraries with a part of the circulation. Outstanding scientific contributions and dissertations are here published as well as projects reports and proceedings of conferences in our house with different contributors from science, economy and politics. With this series we are pursuing the objective to enable a broad access to scientific works and results. We are using the series as well as to promote practically young researchers by the publication of the dissertation of our staff and external doctoral candidates, too. Publications are important milestones on the academic career path. With the series „Reports of the DLR-Institut...

Smart cities, participatory sensing as well as location data available in communication systems a... more Smart cities, participatory sensing as well as location data available in communication systems and social networks generates a vast amount of heterogeneous mobility data that can be used for traffic management. This chapter gives an overview of the different data sources and their characteristics and describes a framework for utilizing the various sources efficiently in the context of traffic management. Furthermore, different types of traffic models and algorithms are related to both the different data sources as well as some key functionalities of active traffic management, for example short-term prediction and control.

As the world population and the traffic demand are constantly inflating, there is a substantial n... more As the world population and the traffic demand are constantly inflating, there is a substantial need to procure a safe and effective method for traffic control and management. Thus, traffic signals operate to manage the flow of vehicles and vulnerable road users through intersections. Intelligent Transport Systems (ITS) technologies based on vehicle connectivity and information exchange may overcome the cons of fixed‐time traffic signals in coping with the unplanned traffic stream. The roadmap for operating connected vehicles in an urban environment is still in the planning phase and in order to achieve sustainable results, a proper management technique must control the flow of vehicles. Green Light Optimal Speed Advisory (GLOSA) utilizes infrastructure and vehicles communication through using current signal plan settings and updated vehicular information in order to influence the intersection approach speeds. This thesis presents a traffic microsimulation study that investigates th...

Variable Speed Limit Systems (VSLS) where gantries are showing speed limits based on, for example... more Variable Speed Limit Systems (VSLS) where gantries are showing speed limits based on, for example, traffic volume or other road or traffic conditions exists on motorways in many countries. The aim ...

Control algorithms used for deciding on the speed limits in variable speed limit systems are cruc... more Control algorithms used for deciding on the speed limits in variable speed limit systems are crucial for the performance of the system. Today, many of the control algorithms used are based on fixed thresholds in speed and/or flow for changing the speed limit. The algorithms are not necessarily reflecting the conditions on the road, which might lead to low traffic efficiency. The authors hypothesis is that by use of a simple and efficient control algorithm that is better in reflecting the conditions on the road, both traffic efficiency and traffic safety could be increased. In this study, four control algorithms used in variable speed limit systems, and fulfilling the above criteria, are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the design of, and the objective with, the control algorithm have impact on the performance. Moreover, the time needed ...

European Transport Research Review

The control algorithm used for deciding on the speed limit in variable speed limit systems is cru... more The control algorithm used for deciding on the speed limit in variable speed limit systems is crucial for the performance of the systems. The algorithm is designed to fulfil the purpose of the variable speed limit system, which can be one or several of the following aspects: increasing safety, increasing efficiency and decreasing environmental impacts. Today, many of the control algorithms used in practice are based on fixed thresholds in speed and/or flow. Therefore, they are not necessarily reflecting the current traffic conditions. Control algorithms with a greater level of complexity can be found in the literature. In this paper, four existing control algorithms are investigated to conclude on important characteristics affecting the performance of the variable speed limit system. The purpose of the variable speed limit system and, consequently, the design of the control algorithm differ. Requirements of the investigated control algorithms are that they should be easy to interpret and the execution time should be short. The algorithms are evaluated through microscopic traffic simulation. Performance indicators related to traffic safety, traffic efficiency and environmental impacts are presented. The results show that the characteristics of the variable speed limit system and the design of the control algorithm will have effect on the resulting traffic performance, given that the drivers comply with the variable speed limits. Moreover, the time needed to trigger the system, the duration and the size of speed limit reductions, and the location of the congestion are factors of importance for the performance of variable speed limit systems.

Transportation Research Procedia

Motorway tra c management systems are useful for improving the tra c conditions on urban motorway... more Motorway tra c management systems are useful for improving the tra c conditions on urban motorways. One of the most common motorway tra c management systems are variable speed limit systems. ese systems adapt the speed limits based on the prevailing tra c conditions measured by roadside detectors and recommended or compulsory speed limits are shown on variable message signs installed on gantries over the road. e systems consist of three parts; the control algorithm used to determine which speed limit to be displayed, a method for estimating the tra c conditions to be used as input for the control algorithm and the infrastructure for application of the variable speed limits. e goal of the systems is o en to increase safety or e ciency. Recent development in the eld of connected vehicles have opened up for a new type of data source, as the status of a connected vehicle and its surroundings can be communicated at arbitrary locations. Hence, by the use of connected vehicles in variable speed limit systems there is a potential of reducing the amount of roadside equipment. It is even possible to control the connected vehicles towards the current speed limit without the use of variable message signs. is allows for the application of variable speed limits at arbitrary locations. e aim of this thesis is to examine how connected vehicles can be used to improve the e ciency of variable speed limit systems. e thesis contribute with new and improved methods using connected vehicles in all three parts of a variable speed limit system. e suggested methods are evaluated by microscopic tra c simulation. e overall iii vii Johansson, it has been a true privilege to share my PhD time with you both as a friend and as a support to my research and the ups and downs coming with it. Henric Jonsson, you have become a good friend and a source to renewed energy at work. You are truly missed at KTS. To my family and friends, thank you for always being there, for your endless support and your love. To my beloved Tobbe, I couldn't have done it without you. ank you for always believing in me. Saga and Emil, I am so thankful for all your love and joy always giving me the strength to keep going.