I PURCHASED THE TESLA MODEL S ON 10/17 WITH 'AUTOPILOT' HARDWARE AND FEATURES I'VE CONSISTENTLY USED AUTOPILOT ON THE HIGHWAY DURING THE FIRST MONTH I'VE HAD THE VEHICLE. THE AUTOPILOT FEATURE USES CAMERAS AND SENSORS TO MAINTAIN SPEED AND LANE AND AVOID COLLISIONS. THIS CAR ALSO FEATURES ANTI-COLLISION FEATURES THAT ARE SUPPOSED TO ENGAGE EVEN WHEN AUTOPILOT IS NOT ENGAGED, TO DETECT BOTH AN OBJECT IN FRONT OF THE CAR AND BRAKE, AS WELL AS DETECT OBJECTS ON EITHER SIDE THAT THE CAR MAY BE HEADED TO COLLIDE WITH AND SWERVE AWAY. THIS FEATURES WERE ALL ENABLED AT TIME OF THE ACCIDENT. AT THE TIME OF ACCIDENT, I HAD AUTOPILOT ENGAGED FOR APPROX 10 MINUTES PRIOR TO ACCIDENT. I WAS STILL WATCHING THE ROAD BUT PERIODICALLY LOOKING AT MY PHONE AS WELL. BEFORE THE ACCIDENT I HAD LOOKED DOWN AT MY PHONE FOR A PERIOD OF TIME I'M NOT SURE ABOUT. I DIDN'T THINK IT WAS LONGER THAN A FEW SECONDS, BUT I CAN'T BE CERTAIN. WHEN I LOOKED UP THE SEMI WAS MERGING IN FRONT OF ME. I WOULD GUESS THAT THE SEMI'S TRAILER WAS PERHAPS 3-4 FEET IN MY LINE, AND I WAS MAYBE 50-100 FEET AWAY. SO IT WAS LESS THAN 1 SECOND PRIOR TO IMPACT. IT WAS SO QUICK THERE WAS NO TIME FOR ME TO EVEN HIT THE BRAKE AND THE CAR WAS NOT BRAKING OR SWERVING TO AVOID COLLISION EITHER. ESSENTIALLY, THE AUTO PILOT DROVE ME RIGHT INTO THE LEFT REAR OF A SEMI TRACTOR TRAILER AT 70 MPH AND THE SENSORS/CAMERAS FOR SOME REASON DID NOT DETECT THIS COLLISION. *TR