My last 3 "accidents" were at 0mph. Both were impacts with my CNC Bridgeport mill. The first time I booted the mill it went to the "x" axis stop and clobbered my wife's car doing it. Then, I moved her car over so it would not hit. But the next two hits were, again, during initial boot-up, when the mill goes to the axis stops...but rather than hitting her car directly, it hit a broom, that hit the grinder, that pushed a barrel...into her car.
I hope I have learned my lesson to give the mill plenty of clearance at start-up!?!