While driving a piece popped off of the passenger door mirror. It flew off and hit the passenger door causing scuff marks before flying into traffic and causing the car behind me to swerve in traffic to avoid it from hitting their car or driving over it, which could have caused an accident. I wasn't able to recover the piece due to the incident occurring on the interstate. I did take the vehicle to the dealership (Serra Toyota - Birmingham, AL) in July and was told by the service technician that they had three other cars to come in with the same issue within the last month. Also, I was told that the entire mirror would have to be replaced since the manufacturer didn't make the piece alone. I was told that it would cost me $800 to replace the entire mirror. I should not be responsible for a faulty piece on the vehicle that was just purchased at the end of April. The technician told me that he would put in a ticket with the manufacturer, but I have not received a response.