Technical development with the goal of achieving zero accidents and zero fatalities is ongoing. The autonomous emergency braking systems that debuted in the late 2000s have proven their value regarding improved safety. However, the technology still presents many challenges because it is not easy to ensure that the system will operate as intended in any environment and at any time. Any system that is unaware of its environment is prone to be excessively conservative, which could adversely affect the efficacy of said system. Situation awareness is a key to resolving this problem. The present study suggests the use of warning braking to gain an awareness of the level of road friction, which is one of the major uncertainties faced on the road. During warning braking, the tire-road maximum friction coefficient is estimated in real time, and a threat assessment is performed adaptively based on the friction information. Because warning braking is momentary and applied with limited dynamics due to issues related to human factors, this study discusses the major considerations and requirements for the key parameters related to warning braking. The performance of the suggested adaptive collision avoidance scheme is verified by means of simulation and experiments.