NOT SURE !!! We were on the Interstate and all of sudden smoke starting coming out of rear end of our vehicle.Our Car started sounding slow and not sounding good, It was me and my husband in the Car. My husband was driving, I started panicking and told my husband about the smoke coming out of the back of our vehicle. Suddenly we saw "Good People "who were on the Interstate right behind our vehicle. They immediately drove passing our car and shouting loud "Get out, Your Car is on Fire". They stopped ahead of us and started calling 911. We both jumped out in a shock. God was with us on this day!!!