  Connected vehicle (CV) technology is among the most heavily researched areas
in both the academia and industry. The vehicle to vehicle (V2V), vehicle to
infrastructure (V2I) and vehicle to pedestrian (V2P) communication capabilities
enable critical situational awareness. In some cases, these vehicle
communication safety capabilities can overcome the shortcomings of other sensor
safety capabilities because of external conditions such as 'No Line of Sight'
(NLOS) or very harsh weather conditions. Connected vehicles will help cities
and states reduce traffic congestion, improve fuel efficiency and improve the
safety of the vehicles and pedestrians. On the road, cars will be able to
communicate with one another, automatically transmitting data such as speed,
position, and direction, and send alerts to each other if a crash seems
imminent. The main focus of this paper is the implementation of Cooperative
Collision Avoidance (CCA) for connected vehicles. It leverages the Vehicle to
Everything (V2X) communication technology to create a real-time implementable
collision avoidance algorithm along with decision-making for a vehicle that
communicates with other vehicles. Four distinct collision risk environments are
simulated on a cost effective Connected Autonomous Vehicle (CAV) Hardware in
the Loop (HIL) simulator to test the overall algorithm in real-time with real
electronic control and communication hardware.
