On April 22, 2022 we were driving east on Hwy 100 in Henderson, TN. We had stopped to make a left-hand turn. A vehicle claimed his brakes went out and hit us from behind going full-speed. Our driver could see he was not stopping and tried to leave the roadway. A vehicle was traveling west (coming towards us) so he couldn't turn to the left. He stated to pull off the roadway into the grass embankment, but didn't get of the road before being struck. My concern is this: our vehicle (cutaway with wheelchair lift added via state contract by Mid-south Bus in Murfreesboro, TN) immediately caught fire and burned to the ground within minutes. If there had been a wheelchair bound passenger tied down in the back of this vehicle, there would've been no way the driver could've got him/her off before being engulfed in flames. The fuel tank is located about 2.5' from the rear of the vehicle. The vehicle has a metal (not fiberglass or plastic) bumper. We have lots of these vehicles. My concern is "what if this happens again an there is a passenger in that wheelchair station?"