Abstract
In this report, an overview and case studies of the vehicle-to-vehicle communication and ranging system using the spread spectrum technique called the boomerang system and improved systems are introduced. The vehicle with the boomerang system can communicate with another vehicle also with this system and, at the same time, the distance between the two vehicles can be controlled. The systems introduced here are important for the practical use of safe driving support systems, which fall under the field of intelligent transport systems (ITS).