Currently the Basic Safety Message (BSM) used by heavy truck tractor-trailers was developed for Vehicle-to-Vehicle (V2V) communications in the U.S. Department of Transportation (DOT) Safety Pilot and uses a simplified bounding box algorithm for conveying the position and heading of the tractor-trailer. However, because of the articulated behavior inherent in a tractor-trailer, this approach does not accurately identify the trailer position or vehicle space for V2V safety applications in all situations. Consequently, in certain situations this can lead to an unacceptable number of false and missed warnings to drivers in surrounding connected vehicles. The U.S. DOT, in partnership with the Crash Avoidance Metrics Partnership (CAMP) and Mercedes-Benz Research & Development North America, Inc. (MBRDNA) conducted a project, Tractor-Trailer Basic Safety Message Development (TT-BSM), to develop technical solutions to this location identification problem for heavy truck tractors with one or more articulated trailers. TT-BSM developed several BSM enhancement approaches to more accurately represent tractor-trailer articulation. Furthermore, the team also completed the system and performance requirements and an assessment of the enhanced BSM impact on internal vehicle platform (OnBoard Equipment (OBE), necessary vehicle sensors on the tractor and the trailer) and external systems (e.g. communications channel loading, other OBE-equipped vehicles, and backend systems). The enhanced BSM can more accurately transmit position and heading for articulated tractor-trailers and thus allows for better safety warnings and fewer false and missed warnings to drivers.

Intersection Collision Avoidance (ICA) based on Dedicated Short Range Communications (DSRC) is one of the most promising applications for vehicle communications. System implementations based on vehicle sensors suffer from field of view limitations that vehicle communications do not exhibit. This makes particularly interesting the adoption of DSRC in combination with other onboard sensors to address intersection crash scenarios. State-of-the-art DSRC-based intersection collision avoidance systems, notably the Intersection Movement Assist (IMA) application, are aimed to issue audible and visual alerts to the driver. This paper describes an implementation of Intersection Collision Avoidance that extends the IMA concept to cover a wider range of intersection collision scenarios and introduces automated braking as a system response when a high risk of a collision is detected and the driver does not react to the alerts.

In Vehicle Safety Communications (VSC) based on IEEE 802.11p, vehicles establish a mutual awareness of their presence by periodically broadcasting status messages, aka beacons. If vehicle density is high and beaconing is not regulated, the channel can become congested, impairing reception performance and safety benefit. As a countermeasure, a number of congestion control approaches have been suggested, adapting transmit (Tx) power, beacon generation rate (Tx rate), or both. However, in general these approaches did not show what the optimal outcome for congestion control would be and how and why their solution would lead to the desired result. In this work, we analyze answers to the first question and provide a methodology for the second. We systematically derive a joint power/rate control strategy for VSC which optimizes reception performance for a targeted sender-receiver distance. We start by laying out why we consider average (or percentile of) packet Inter-Reception Time (IRT) at the targeted awareness distance to be a suitable metric for our purpose. Then, we analyze a wide range of Tx parameters to identify which combinations optimize reception in a homogeneous scenario. We show that for each sender-receiver distance, there is an optimal Tx power which, unlike the corresponding Tx rate, is independent of node density. In addition, we analyze the Pareto optimal Tx parameter combinations for two groups of vehicles with different target distances adapting at the same time. We show that the majority of these combinations use the same Tx power as identified in the homogeneous case. We conclude that a simple and efficient strategy to optimize reception performance is to select Tx power w.r.t. the targeted distance and to adapt Tx rate w.r.t. channel load.

In this 12th issue of the Automotive Networking and Applications Series, we are pleased to present two articles on using vehicles as a temporary roadside infrastructure to improve the performance of vehicular ad-hoc networks - without the use of fixed roadside units, and on mechanisms for event data recorders in vehicles that seek to protect the privacy of drivers and passengers while allowing access by the authorities in case of accidents, respectively.

The idea of shared certificates is to assign each certificate to a large enough group of vehicles so that it will be difficult for adversaries to link a certificate to any particular vehicle. This chapter focuses on statistically shared certificates. That is, a certificate is assigned to each vehicle according to a probability distribution so that a random group of vehicles shares each certificate. The chapter first discusses the properties and limitations of the original combinatorial certificate scheme. It discusses the potential solutions to improve the scalability and robustness of statistical certificate sharing. When a certificate assigned to a misbehaving vehicle is revoked, all the other vehicles sharing this certificate will also not be able to use it. This effect is referred to as certificate revocation collateral damage. Certified interval is a crucial indicator of a certificate scheme's robustness. Controlled Vocabulary Terms robust control

Provides an up-to-date, in-depth look at the current research, design, and implementation of cooperative vehicle safety communication protocols and technologyImproving traffic safety has been a top concern for transportation agencies around the world and the focus of heavy research and development efforts sponsored by both governments and private industries. Cooperative vehicle systemswhich use sensors and wireless technologies to reduce traffic accidentscan play a major role in making the world's roads safer.Vehicle Safety Communications: Protocols, Security, and Privacy describes fundamental issues in cooperative vehicle safety and recent advances in technologies for enabling cooperative vehicle safety. It gives an overview of traditional vehicle safety issues, the evolution of vehicle safety technologies, and the need for cooperative systems where vehicles work together to reduce the number of crashes or mitigate damage when crashes become unavoidable.Authored by two top industry professionals, the book:Summarizes the history and current status of 5.9 GHz Dedicated Short Range Communications (DSRC) technology and standardization, discussing key issues in applying DSRC to support cooperative vehicle safetyFeatures an in-depth overview of on-board equipment (OBE) and roadside equipment (RSE) by describing sample designs to illustrate the key issues and potential solutionsTakes on security and privacy protection requirements and challenges, including how to design privacy-preserving digital certificate management systems and how to evict misbehaving vehiclesIncludes coverage of vehicle-to-infrastructure (V2I) communications like intersection collision avoidance applications and vehicle-to-vehicle (V2V) communications like extended electronic brake lights and intersection movement assistVehicle Safety Communications is ideal for anyone working in the areas ofor studyingcooperative vehicle safety and vehicle communications.

At the physical layer (PHY), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard sets the specifications for frame transmissions and receptions over the air. This includes signal modulations, frame formats, and the way different elements of incoming frames need to be interpreted at the receivers. This chapter focuses on PHY operations relevant to vehicle safety communications after a review of the most relevant IEEE 802.11 PHY mechanisms. It describes how the wireless access in vehicular environments (WAVE) PHY layer can be accurately modeled in software. The chapter further describes a network simulator (ns) that was used to generate most of the results on WAVE radio performance. IEEE 802.11a radios use orthogonal frequency division multiplexing (OFDM) to transmit over the air. Controlled Vocabulary Terms OFDM

This chapter first provides a brief overview of the leading fourth-generation (4G) cellular technology — the Long-Term Evolution (LTE). It then uses examples to illustrate the technical feasibility and potential issues to be addressed when using LTE to support vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) safety communications. The leading 4G cellular network standard is the LTE developed by the Third-Generation Partnership Project (3GPP). LTE offers significantly higher capacities and lower delays than third-generation (3G) cellular networks. As LTE deployment progresses worldwide, 3GPP has been developing LTE Advanced. Using cellular networks for supporting the communications of a large number of vehicles can have a profound impact on the cellular networks and requires an in-depth examination of several fundamental issues. Third-generation (3G) cellular networks support cell broadcast service (CBS) that broadcasts low-rate text messages to all receivers inside one cellular cell. Controlled Vocabulary Terms 3G mobile communication; 4G mobile communication; Long Term Evolution

The articles in this special section focus on automotive networking and applications.

In 1998, the U.S. Congress enacted the transportation equity act for the 21st century [TEA98], which directed the Federal Communications Commission (FCC) to consider the spectrum needs "for the operation of intelligent transportation systems, including spectrum for the dedicated short-range vehicle-to-wayside wireless standard." In the United States, the 75-MHz spectrum between 5.850 and 5.925 GHz is referred to as 5.9 GHz dedicated short-range communications (DSRC). It is often necessary to specify 5.9 GHz when referring to DSRC to differentiate the new spectrum from the older 900 MHz band of the same name, used for electronic toll collection. The European Union (EU) also recognized the importance of a dedicated spectrum for ITS. The European DSRC spectrum is structured into five 10-MHz channels, as opposed to the seven 10-MHz channels allotted to DSRC in the United States. Vehicle-to-vehicle (V2V) safety communications are not an officially intended usage of DSRC technology in Japan. Controlled Vocabulary Terms radio spectrum management; transportation