I was driving on the SB 55fwy in light stop and go traffic and had my ACC w/ traffic aware system engaged. My car was doing as it normally does, keeping a safe distance to the vehicle in front of me, automatically slowing, stopping and accelerating at a safe speed for the conditions. This feature I had been using on my car since I originally purchased it and paid for these safety features. When traffic was not stopped it was traveling between 15-20mph. All of the sudden my dashboard lit up with error messages, audible warnings, and check engine light, all flashing and beeping at me and before I quickly glanced at the dash to the alarming warnings, I had rear ended the car in front of me. This took me by complete shock as my car had always been overly cautious about applying emergency braking in close situations. This time it did nothing. The error message said Adaptive Cruise Control sensor had failed and along with that it had disabled all of the safety features I had become accustomed to and paid extra for, including, the emergency braking and front end collision warning. This caused almost $14k in damage to my vehicle and more so potentially could have put my entire family in danger. The sensor failure caused the accident, the damage to the other car that I was traveling behind and any potential injuries from the driver of that car. I have given this same statement to my insurance company, however no one has reached out to investigate the cause of the failure, not even the