Security of Intelligent Transportation Systems (ITS) heavily depends on the security of the underlying components that create such a smart ecosystem. Adaptive Cruise Control (ACC) is embedded into most modern vehicles. In this report, we study the situations that the two vehicles involved in a cruise control scenario create. More precisely, after breaking down the phases the two vehicle go through (especially the ego one), we show how a simple formula can be used to predict collisions in hard brake cruise control scenarios.