New cooperative intelligent transportation system (C-ITS) applications become enabled thanks to advances in communication technologies between vehicles(V2V) and with the infrastructure (V2I). Communicating vehicles share information with each other and cooperate, which results in improved safety, fuel economy, and traffic efficiency. An example of a C-ITS application is platooning, which comprises a string of vehicles that travel together with short inter-vehicle distances (IVDs).

Any solution related to C-ITS must comply with high safety requirements in order to pass standardization and be commercially deployed. Furthermore, trusted safety levels should be assured even for critical scenarios.

This thesis studies the conditions that guarantee safety in emergency braking scenarios for heterogeneous platooning, or string-like, formations of vehicles. In such scenarios, the vehicle at the head of the string emergency brakes and all following vehicles have to automatically react in time to avoid rear-end collisions. The reaction time can be significantly decreased with vehicle-to-vehicle (V2V) communication usage since the leader can explicitly inform other platooning members about the critical braking.

The safety analysis conducted in the thesis yields computationally efficient methods and algorithms for calculating minimum inter-vehicle distances that allow avoiding rear-end collisions with a predefined high guarantee. These IVDs are theoretically obtained for an open-loop and a closed-loop configurations. The former implies that follower drives with a constant velocity until braking starts, whereas in the latter, an adaptive cruise control (ACC) with a constant-distance policy serves as a controller. In addition, further optimization of inter-vehicle distances in the platoon is carried out under an assumption of centralized control. Such an approach allows achieving better fuel consumption and road utilization.

The performed analytical comparison suggests that our proposed V2V communication based solution is superior to classical automated systems, such as automatic emergency braking system (AEBS), which utilizes only onboard sensors and no communication. Wireless communication, enabling to know the intentions of other vehicles almost immediately, allows for smaller IVDs whilst guaranteeing the same level of safety.

Overall, the presented thesis highlights the importance of C-ITS and, specifically, V2V in the prevention of rear-end collisions in emergency scenarios. Future work directions include an extension of the obtained results by considering more advanced models of vehicles, environment, and communication settings; and applying the proposed algorithms of safety guaranteeing to other controllers, such as ACC with a constant time headway policy.

Advances in technologies for vehicular communication enable new applications for Cooperative Intelligent Transportation Systems (C-ITS). Communicating vehicles share information and cooperate, which allows for improved safety, fuel economy, and traffic efficiency. Platooning – a coordinated string of vehicles with small Inter-Vehicle Distances (IVDs) – comprises one such C-ITS application. Any C-ITS application must comply with high safety requirements to pass standardization and be commercially deployed. Moreover, trusted solutions should be guaranteed even for critical scenarios or rare edge cases. This thesis presents two sets of contributions related to cooperative automated driving. Firstly, it provides conditions ensuring safe platooning or vehicle following. Secondly, it introduces an ethical framework to guide autonomous decision-making in scenarios involving imminent collisions. In the first set of contributions, we consider emergency braking scenarios for vehicles driving in a platoon or following each other. In such scenarios, the lead vehicle suddenly brakes. This requires swift responses from followers to prevent rear-end collisions. Here, Vehicle-to-Everything (V2X) communication has the potential to significantly reduce reaction times by allowing the lead vehicle to notify followers of the emergency braking. The presented safety analysis yields computationally efficient methods and algorithms for calculating minimum IVDs for rear-end collision avoidance. The IVDs are computed for closed-loop and open-loop configurations. The open-loop configuration implies followers drive with a constant velocity until the onset of braking, whereas in the closed-loop configuration, a controller is used under some restrictions. In addition, a centralized approach for optimization of IVDs in platoon formations is carried out. Such an approach allows for improved fuel consumption and road utilization. An analytical comparison shows that our proposed Vehicle-to-Vehicle (V2V) communication-based solution is superior to classic automated systems, such as automatic emergency braking system, which utilizes only onboard sensors. Wireless communication provides intentions to vehicles almost immediately, which allows for smaller IVDs while guaranteeing the same level of safety.

In the second set of contributions, an ethical framework to guide autonomous decision-making is presented. Even though collisions resulting from edge cases are unlikely, it is essential to address them in motion planning logic for autonomous vehicles. Decisions made in such situations should always prioritize ethical considerations, such as saving human lives. Adhering to ethical principles in the development and deployment of autonomous vehicles is essential for fostering public understanding and acceptance. The thesis presents a framework of ethical V2X communication, where V2X is acknowledged as an essential means for enabling autonomous vehicles to perform coordinated actions to meet certain ethical criteria. The presented framework demonstrates how the risk or harm resulting from unavoidable collisions can be mitigated or redistributed under ethical considerations through cooperation between vehicles. Overall, the presented thesis highlights the importance of C-ITS and, specifically, V2X communication in managing emergency scenarios. V2X communication enables faster response times and facilitates cooperative maneuvers, which helps preventing rear-end collisions or mitigating their consequences under ethical considerations. Future work directions include an extension of the obtained results by considering more advanced models of vehicles, environment, and communication settings; and applying the proposed frameworks to more complicated traffic scenarios.