TL* THE CONTACT RENTED A 2016 MERCEDES-BENZ CLA250. WHILE DRIVING 45 MPH, THE CONTACT'S VEHICLE CRASHED INTO THE REAR OF ANOTHER VEHICLE. THE CONTACT STATED THAT THE BRAKE PEDAL WAS DEPRESSED AND FAILED TO OPERATE AS INTENDED. THE CONTACT ALSO STATED THAT THE AUTONOMOUS BRAKING SYSTEM FAILED TO OPERATE AS INTENDED. THE AIR BAGS FAILED TO DEPLOY. THE VEHICLE WAS TOWED TO AN INDEPENDENT MECHANIC. THERE WERE NO INJURIES. A POLICE REPORT WAS FILED. THE RENTAL AGENCY WAS NOTIFIED OF THE FAILURE. THE MANUFACTURER WAS NOT NOTIFIED. THE VIN AND FAILURE MILEAGE WERE UNKNOWN.