I PUT THE CAR IN PARK (ENGINE STILL RUNNING) TO GO OUT OF THE VEHICLE TO TALK TO SOMEONE. I TURNED AROUND AND THE CAR WAS ROLLING BACKWARDS. IT GAINED SPEED AS IT APPROACHED A HILL, CROSSED OVER A SIDEWALK AND SLAMMED INTO A TREE. I HAD 2 BIKES ON A BIKE RACK ON THE BACK, WHICH TOOK THE BRUNT OF THE CRASH. THE BIKES, THE BIKE RACK AND THE REAR OF THE CAR WERE CRUSHED. THERE WAS NO WARNING NOISE OR OTHER INDICATION THAT MY CAR HAD NOT GONE INTO PARK.