I took delivery of my new P90D last weekend (trading in my model 85 from 2013) and downloaded Firmware 7.1 two days ago. I had used autopilot for a few days with Firmware 7.0 and found it wonderful (astounding). Today was the first day I tried it using 7.0. At about 8:30 AM this morning on I90 (road conditions perfect, visibility good), I was doing about 60 MPH and switched on Autopilot. I initiated a lane change with my turn signal and the car switched lanes seamlessly. My car automatically modulated my speed (with a two car distance) with the car in front of me, and I was cruising along happily when the car in front of me changed lanes and my car caught up to the car in front of him. After following this new car for a few minutes, the traffic began to slow. My car slowed as well. But when the car in front of me came to a complete stop (not a sudden emergency stop, but rather a gradual stop), I expected my car to do the same (as it had been doing previously). It didn't. I slammed on the brakes in that dreadful instance before I realized my car wouldn't stop in time, but I still hit the car in front of me (while going maybe 5-10 MPH). I'd like to mention that I consider myself a very safe driver and have never been involved in any accident before (I'm 52). I damaged that car's rear bumper and cracked the plastic cover on my new Tesla (see attached photo). After the police came (the other driver insisted we file an accident report) and I received a $120 ticket, I called Tesla's technical assistance. The gentleman I spoke with told me that the Autopilot function is "flawless" and that it was my responsibility, as the driver, to avoid any collision. I asked to speak with his supervisor who told me that this was the first time anything like this has ever happened, and found it "very strange." They were clearly intimating that I did something wrong.