Cooperative Intelligent Transport Systems Research Articles

CAM-Infrastructure: a novel solution for service advertisement in Cooperative Intelligent Transportation Systems

Cooperative Intelligent Transportation Systems (C-ITS) are gaining ground and currently are almost part of our everyday life. A C-ITS environment can provide numerous services that soon will become essential to roads’ users. The latter resides in improvement of road safety, entertainment, and commercial services. However, in order to provide such services, the C-ITS environment needs an advertisement and dissemination service for them. Indeed, users have to be aware of the available services in order to request them if needed. Current standards of service announcement show their limits, especially regarding the interoperability between communication profiles. For this reason, in this paper, we describes our new service advertisement solution called CAM-Infrastructure. The latter is compliant with ETSI standards and is deployed in SCOOP@F, a nationwide scale project.

On the Interrelation of Security, QoS, and Safety in Cooperative ITS

Cooperative intelligent transport system (C-ITS) is an emerging technology that enables secure and safe road travel using wireless communications. Vehicles regularly share their mobility information with the neighborhood road traffic and infrastructure-based road side units using cooperative awareness messages (CAMs) to develop a local dynamic map for safety applications. Since the applications provided by C-ITS are related to human safety, reliable as well as secure communications are required. To protect the vehicular network from untrusted data of malicious users that could cause network congestion and reduce vehicle safety, ITS standards have proposed various security procedures. In this paper, we analyze the interrelation between security, quality of service (QoS), and safety awareness of vehicles in C-ITS. To formulate an accurate measure of vehicle safety awareness, we first propose novel vehicle and infrastructure centric metrics that use the number of received CAMs, their accuracy, safety importance, and vehicle heading. We then implement the standard CAM signature and verification procedure in the ITS standard. Using simulation results and our proposed metrics, we show the impact of security signature and verification speed on the level of vehicle awareness and, hence, QoS in different road traffic conditions.

Service-Oriented Cooperation Models and Mechanisms for Heterogeneous Driverless Vehicles at Continuous Static Critical Sections

As driverless vehicles are increasingly becoming possible, so does the use of such vehicles as intelligent carriers in different domains. Intelligent transportation systems (ITSs) show increasingly heterogeneous, cyber-physical, cooperative, and service-oriented features and are beginning to be merged with the emerging cyber-physical-social systems. Given this new trend, how to make these intelligent vehicles cooperate more safely and efficiently with one another according to novel constraints, such as mission type and quality-of-service (QoS), has become a vital aspect of cooperative ITS (C-ITS). With these emerging characteristics, the classical passing-through-intersection problem has gained new connotations, worth further exploring. After analyzing the essences of this new problem, service-oriented cooperation models and mechanisms for whole autonomous vehicles approaching intersections are investigated in this paper. First, related traffic objects and possible vehicular behaviors are abstracted and modeled with the cyber-physical cooperative features and QoS constraints. A new reservation-based scheduling procedure is then conducted by employing the concepts of vehicle-to-infrastructure communication, and typical vehicular passing-through behaviors and several spatial-temporal constraints are designed to coordinate vehicles passing through an intersection divided as a series of continuous static critical sections. Given these considerations, a priority-based centralized scheduling algorithm, named cs PriorFIFO, which adopts a novel priority inheritance mechanism to promote the traffic QoS of emergent vehicles, is proposed. Finally, all these designs are implemented in a traffic simulator named QoS-CITS, and the functions and the performance of these studied methods are verified and compared.

Improving regional road network resilience by optimised traffic guidance

ABSTRACTIn this paper, a new approach for improving the traffic performance of regional road networks during the recovery period following a disaster life cycle is presented. Regional road networks are often uncongested and have sparse and long-spanning link densities. Consequently, they are more impacted by natural disasters and thereby by potential road closures that may be imposed afterwards. Information about road closures after disruptive events can be transmitted through roadside information dissemination methods such as variable message signs, Cooperative-Intelligent Transport Systems or highway advisory radio. This paper proposes an optimisation model to find optimal location of roadside guidance devices across a regional road network for improving total travel time (TTT) within the network. To achieve this, firstly, a network design model is formulated using a bi-level framework and implemented to find the optimal locations of roadside guidance devices that lead to reducing the TTT of a disrupted network. Secondly, two methods for solving the formulated problem are presented, an exact solution method called SO-relaxation that cuts the solution space using system optimum traffic assignment. The other method is a hybrid-GA that is a heuristic solution method. Results show that locating guidance devices optimally in a disrupted network leads to a more resilient road network in which the post-disaster TTT of the network during recovery phase is less than when no action is taken. It is also shown that the improvement achieved by roadside guidance is a function of available resources and the road users willingness to obey the guidance provided.

A validation tool for cooperative intelligent transport systems

This paper aims to present a set of tools that could be used in order to check the conformance of an Cooperative-Intelligent Transport System (C-ITS). These tools will consider each C-ITS component, i.e. C-ITS-R Road Side Units (RSU), C-ITS-V On-Board Unit (OBU), C-ITS-C (Central Server) with their specific features as location precision for an OBU and adequate forwarding of security events for an RSU.We first tackle in this study the conformance testing aspect for each component (in fact a C-ITS component has to respect all the basic specifications) before checking the interoperability of all components (in order to ensure a correct functioning when they work together). Basic specifications have been mainly described by standardisation institutes as ETSI or IEEE. But some additional specifications could be considered for particular purposes (for example, car manufacturers do not all agree on the pertinent moment to inform drivers on next hazardous events).This framework has been experimented with various RSUs and OBUs from different providers and many troubles have been detected. Most of the bugs are due to a wrong interpretation of specifications. But, in some other cases, troubles reveal that specifications have been proposed with incorrect behaviours. The main conclusion is that such frameworks have to be improved and deployed widely in order to facilitate the deployment of large scale Intelligent Transport Systems.

Correction: Moreno, A., et al. Design of a Cooperative ITS Architecture Based on Distributed RSUs.

n/a.

Cooperative Intelligent Transport Systems in Europe: Current Deployment Status and Outlook

The cooperative intelligent transport system (C-ITS) (also known as connected vehicle technology in the United States) is an application using vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications, at a carrier frequency of 5.9 GHz, to increase road traffic safety and efficiency in Europe. In this article, we hope to shed light on the current status of the C-ITS in Europe and the activities that must be accomplished before deployment can commence in 2019, the date announced by the CAR-2-CAR Communication Consortium (C2C-CC). There is immense activity regarding the launch of the C-ITS in Europe, and the automotive industry is also currently planning for the future.

AIM reference track - test site for V2X communication systems and cooperative ITS services

Cooperative intelligent transport systems (C-ITS) based on Vehicle2X (V2X) communication are currently under development in the automotive industry and regarded to be in mass-production in the near future. In order to develop and test cooperative ITS services, the Institute of Transportation Systems of the German Aerospace Center (DLR) operates a large-scale test site in the city of Braunschweig, Germany. This research infrastructure facilitates test activities, measurements as well as evaluation activities for C-ITS in a real-life environment.

Integration of vulnerable road users in cooperative ITS systems

IntroductionThis paper describes the development of an architecture for the integration of Vulnerable Road Users (VRUs), i.e. pedestrians, cyclists and powered two-wheelers (PTWs) in Cooperative ITS (C-ITS) systems, and the requirements for VRU devices.MethodsThis paper starts with a literature overview on research related to safety applications using communication between vehicle and VRU, and an analysis of the different use cases for C-ITS for VRUs. An architecture is developed, starting from an architecture of C-ITS systems and incorporating the different alternative configuration for VRUs. Starting from the architecture and the use cases, the requirements for VRU devices are defined. Finally, a roadmap regarding C-ITS applications for VRUs is developed.ResultsC-ITS technologies allow to communicate with low latency in highly dynamic environments. C-ITS will be integrated in vehicles and can also become available for VRUs, either as an application on a smartphone or as a dedicated device, which can be integrated in the VRU’s vehicle. Two levels of use cases can be identified: awareness of the presence of VRUs near potentially dangerous situations, and collision risk warning, based on trajectories of the road users. A roadmap was developed aligned with the roadmap of the automotive industry.ConclusionsAwareness related use cases are relatively close to the market, as they do not put stringent requirements to the (localization) sensors at infrastructure or vehicles. For the collision risk warning use case, the technical requirements for VRU devices towards sensor accuracy and calculation capabilities are challenging. Other challenges are power consumption, context sensitivity, channel congestion, privacy and security of messages. Standardisation of the messages exchanged between VRUs and other road users and infrastructure is a key issue.

ITS‐G5 performance improvement and evaluation for vulnerable road user safety services

Cooperative intelligent transportation system (C-ITS) allows to improve safety of vehicles through communications between vehicles and infrastructure. C-ITS may also improve the safety of vulnerable road users (VRUs), but work on this issue is still in an early stage. ITS-G5 (IEEE 802.11p), the main technology for vehicle-to-vehicle time-critical communications, allows to deliver safety information over a rather long range with low latency, but obstacles in the link path and a large amount of vehicles sending at the same time may reduce performance. In this study, the authors assess and optimise the performance of ITS-G5 for time-critical safety conflict scenarios between vehicles and VRUs. The authors have tested various non-line-of-sight (NLOS) scenarios in urban environments and line-of-sight (LOS) simulations to support C-ITS message prioritisation and scalability with different amount of vehicles. Example use cases with NLOS include pedestrians crossing streets from behind objects, and low-visibility scenarios, e.g. when VRU is behind a vehicle, behind a queue of vehicles, between vehicles, behind trees/bushes or behind a building. The LOS simulations utilise fuzzy weighted queueing mechanism for congestion control to overcome the packet losses and for data prioritisation. Based on these results, the applicability of ITS-G5 for VRU applications is assessed and performance improved.

Towards seamless inter-technology handovers in vehicular IPv6 communications

Network mobility plays an important role in communications when using different access networks while maintaining application sessions. This is the case of vehicular networks used by the emerging Cooperative Intelligent Transport System (C-ITS), where vehicles are constantly moving, changing their access network. Standardization bodies like IETF, and particular proposals in the literature, have already defined mobility mechanisms by using widely used Internet technologies. The usefulness of these mechanisms in vehicular networks is clear when using IPv6, however, its performance suffer from the high mobility of nodes, the fluctuating performance of communication technologies, and the need for a decision mechanism to choose a proper attachment point among the available access networks on roads. For this reason, here we propose an instantiation of the ISO/ETSI reference architecture for vehicular cooperative systems, by deploying a real vehicular network based on IPv6, as well as a mobility service provided by Network Mobility Basic Support (NEMO) and the Multiple Care of Addresses Registration (MCoA) extension. This mobility solution is embedded into a framework that integrates the IEEE 802.21 technology, which provides a greater control over the handover process. The resulting architecture not only provides a seamless handover but also supports the decision making when searching for the most suitable target network. Our experiments reveal that our combined NEMO/MCoA/802.21 system within a vehicular communication stack is able to provide uninterrupted communications during handovers with a dramatic reduction in the time needed by this process.

Cooperative ITS – A Strategic Way to Ensure Road Safety

Abstract This work sums up investigations for creating cooperative ITS carried out in the European Union and studies their results and their role in road safety ensuring. An integrated approach to substantiation of the necessity of development of cooperative ITS within the coordinated development of the transport infrastructure, its arrangement, traffic management systems, development of intelligent onboard transportation systems is implemented. Viability of creating high-tech yards of cooperative ITS is shown and conclusions on the necessity of activating works on their creation in Russia are substantiated. In particular, viability of creating the yard for developing ITS technologies in St. Petersburg and high-priority measures for its creation are substantiated.

Current Trends of Road-traffic Infrastructure Development

Abstract Recently many countries place stakes on such technologies as autonomous transportation vehicles and cooperative intelligent transportation systems. The prototypes have been built and undergo various tests in different countries worldwide, including Russia. However, this phenomenon is nothing else than the next stage of intelligent transportation systems (ITS) development, which has been aimed at complete change not only the idea of ITS, but the very process of conveyance of cargoes and passengers and a process of control of transportation vehicles.

Computer Modelling of Cooperative Intelligent Transportation Systems

The Cooperative Intelligent Transportation Systems (C-ITS) are one of the most important parts of intelligent transportation support. The possibilities of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication modelling and computer simulation are presented in this paper. The results of V2V and V2I communications simulation, with regard to expected C-ITS services are shown. Gathered results are evaluated in consideration of current and future communication technologies (VANET, 4G, 5G) capabilities.

Optimization of lane-changing distribution for a motorway weaving segment

Article free to read on journal website The traffic in a weaving segment is subject to lane-changing turbulence in excess of that normally present on basic motorway segments. Empirical studies have observed a lane-changing concentration problem, as traffic flow increases, which can cause flow break down and congestion. This paper focuses on the lane-changing concentration problem in weaving segments. A Cooperative Intelligent Transport System (C-ITS) advisory has been shown to alleviate such a lane-changing concentration problem. The advisory aims to distribute the lane-changing along the weaving segment. Unlike previous methods in the literature, where weaving vehicles are assigned according to fixed distributions, this paper proposes an algorithm to optimize the lane-changing distribution. The proposed optimization algorithm was developed based on particle swarm optimization. The optimized lane-changing distribution for a one-sided motorway weaving segment using microscopic simulation has been evaluated. The initial results show that the proposed algorithm could be used as a successful optimization technique for the lane- changing concentration problem.

WAVE Communication-based V2I Channel Modeling

Wireless access in vehicle environment (WAVE) communication is currently being researched as core wireless communication technologies for cooperative intelligent transport systems (C-ITS). WAVE consists of both vehicle to vehicle (V2V) communication, which refers to communication between vehicles, and vehicle to infrastructure (V2I) communication, which refers to the communication between vehicles and road-side stations. V2I has a longer communication range than V2V, and its communication range and reception rate are heavily influenced by various factors such as structures on the road, the density of vehicles, and topography. Therefore, domestic environments in which there are many non-lines of sight (NLOS), such as mountains and urban areas, require optimized communication channel modeling based on research of V2I propagation characteristics. In the present study, the received signal strength indicator (RSSI) was measured on both an experience road and a test road, and the large-scale characteristics of the WAVE communication were analyzed using the data collected to assess the propagation environment of the WAVE-based V2I that is actually implemented on highways. Based on the results of this analysis, this paper proposes a WAVE communication channel model for domestic public roads by deriving the parameters of a dual-slope logarithmic distance implementing a two-ray ground-reflection model.

Breaking the Gridlock of Spatial Correlations in GPS-Aided IEEE 802.11p-Based Cooperative Positioning

Spatial correlations found in vehicular mobility are jeopardizing the precision level of cooperative positioning for future Cooperative Intelligent Transport System (C-ITS) applications. Bayesian filters traditionally assume independence of the measurement noise terms over space between different vehicles and over time at each vehicle, whereas they are actually correlated due to the local continuity of physical propagation phenomena (e.g., shadowing, multipath, etc.) under highly constrained vehicular mobility. In this paper, we break this gridlock by proposing an innovative data fusion framework capable of mitigating these effects to maintain the positioning precision level under severely correlated environments. We first illustrate the dramatic impact of correlated noise affecting both global positioning system and vehicle-to-vehicle (V2V) received power observations. Then, we propose a new generic data fusion framework based on a particle filter supporting three complementary methods to decorrelate measurement noises in a globally asynchronous context. Compared with conventional cooperative positioning, simulations performed in canonical vehicular scenarios (highway, urban canyon, tunnel) show that our proposed approach could provide up to 60% precision improvement in correlated environments, while matching by less than 15-20% deviation, an optimal cooperative positioning scheme considered under independent measurements.

Assessing the safety effects of cooperative intelligent transport systems: A bowtie analysis approach

The safety effects of cooperative intelligent transport systems (C-ITS) are mostly unknown and associated with uncertainties, because these systems represent emerging technology. This study proposes a bowtie analysis as a conceptual framework for evaluating the safety effect of cooperative intelligent transport systems. These seek to prevent road traffic accidents or mitigate their consequences. Under the assumption of the potential occurrence of a particular single vehicle accident, three case studies demonstrate the application of the bowtie analysis approach in road traffic safety. The approach utilizes exemplary expert estimates and knowledge from literature on the probability of the occurrence of accident risk factors and of the success of safety measures. Fuzzy set theory is applied to handle uncertainty in expert knowledge. Based on this approach, a useful tool is developed to estimate the effects of safety-related cooperative intelligent transport systems in terms of the expected change in accident occurrence and consequence probability.

Fusion of Perception and V2P Communication Systems for the Safety of Vulnerable Road Users

With cooperative intelligent transportation systems, vulnerable road users (VRU) safety can be enhanced by multiple means. On the one hand, perception systems are based on embedded sensors to protect VRUs. However, such systems may fail due to the sensors’ visibility conditions and imprecision. On the other hand, vehicle-to-pedestrian (V2P) communication can contribute to the VRU safety by allowing vehicles and pedestrians to exchange information. This solution is, however, largely affected by the reliability of the exchanged information, which most generally is the GPS data. Since perception and communication have complementary features, we can expect that a fusion between these two approaches can be a solution to the VRU safety. In this paper, we propose a cooperative system that combines the outputs of communication and perception. After introducing theoretical models of both individual approaches, we develop a probabilistic association between perception and V2P communication information by means of multi-hypothesis tracking. Experimental studies are conducted to demonstrate the applicability of this approach in real-world environments. Our results show that the cooperative VRU protection system can benefit of the redundancy coming from the perception and communication technologies both in line-of-sight (LOS) and non-LOS conditions. We establish that the performances of this system are influenced by the classification performances of the perception system and by the accuracy of the GPS positioning transmitted by the communication system.

Dependability of Decentralized Congestion Control for Varying VANET Density

IEEE 802.11p is an amendment to the IEEE 802.11 standard for Wireless Access in Vehicular Environments (WAVE). Lower layer wireless transmission formats and protocols are defined for both vehicle-to-infrastructure and vehicle-to-vehicle communication links to support cooperative intelligent transport systems. The medium access control (MAC) layer uses carrier sensing as a means for detecting the busy state of the radio channel before transmitting. In heavily loaded vehicular ad hoc networks (VANETs), the channel access delay, when attempting to access the channel, unpredictably increases when it is sensed as busy. The European Telecommunications Standards Institute (ETSI) defines safety-related messages. These messages require a dependable behavior of the communication link. In this context, dependable behavior translates to the reliable delivery of data packets within a specified deadline regardless of changes in traffic density. Unfortunately, the WAVE amendment does not fulfill the requirements for such dependable behavior. This contribution reports on performance evaluations by simulation studies of the WAVE MAC and the decentralized congestion control (DCC) mechanism specified by the ETSI in addition to the existing enhanced distributed channel access. The simulation scenario under study is a two-VANET-merging highway situation. The MAC protocol has to adapt to variable traffic densities in this scenario. The performance is evaluated in terms of coverage range and MAC-to-MAC delay reliability and DCC state stability. Furthermore, a novel performance indicator is defined, evaluated, and discussed, which the authors of this work have named data novelty. Finally, a multistate-active DCC mechanism is proposed, which achieves a dependable behavior.