While driving on an interstate, I started reducing my speed as I was approaching my exit. Before I could exit, my car automatically came to a complete stop. I was rear ended by a truck that was behind me. There were no vehicles or objects in front of me. 911 was called. The passenger in my car had to be transported to the hospital. My car and the truck had to be towed away. No warning lights appeared. My insurance company will be inspecting the car at the tow shop. Everyone involved safety was put at risk. We are thankful we are alive because this could have been worse.