Advisory Speed Estimation for an Improved V2X Communications Awareness in Winding Roads

The European Telecommunications Standards Institute (ETSI) establishes a Decentralized Congestion Control (DCC) which triggers the so-called Cooperative Awareness Message (CAM) depending on vehicle kinematics. However, this algorithm hence called CAM-DCC represents a challenge in the triggering rules of these messages. In particular, it lacks (i) awareness of the neighboring vehicles and (ii) efficient use of the channel bandwidth. Consequently, information gaps related to the road environment might give rise to non-compliances in the application layer requirements of the vehicles, which could potentially threaten the drivers' safety, most particularly in hazardous roads. To overcome these flaws, we first study the CAM generation trigger focused on the vehicle heading in risky curves or winding roads. Then, we evaluate both scenarios tuning different triggering thresholds and including additional mechanisms such as the comparison of the current speed respect to the estimated advisory speed over time. Different computer simulations have been conducted in two real road sections to validate our proposal. Results reveal significant better performance in terms of awareness and channel usage.