WAS DRIVING 25 MILES AN HOUR DOWN SMALL HILL, THE CAR IN FRONT OF ME STOPPED. I HIT THE BRAKES AND THE CAR DIDN'T STOP IT FELT AS IF I WAS PUSHING THE ACCELERATOR LIKE WHEN PUSHING BUTTON! TO SPEED UP CRUISE CONTROL AND IT SLOWLY INCREASES SPEED. I SLAMMED BOTH FEET TO THE BRAKE AND WENT TO REACH FOR EMERGENCY BRAKE BUT NEVER MADE IT. I HIT THE OTHER CAR. LAST THING I REMEMBER IS HEARING METAL CRUNCH, THE NEXT THING I REMEMBER IS SMOKE, TOP OF MY HEAD ON LEFT SIDE HAIRLINE ACHED LOOKED IN MIRROR AND SAW BLOOD. STARTED LOOKING FOR MY PHONE ON THE DASH BUT IT WAS BROKEN.COULD HEAR SOMEONE TALKING, THEN PEOPLE WERE WALKING UP TO CAR. WHEN THE OFFICER GOT THERE HE ASKED WHAT I HIT MY HEAD ON I DIDN'T KNOW, HE ASKED IF I HAD MY SEATBELT ON I SAID YES. I TOLD HIM MY CAR WOULDN'T STOP. REALIZED WHEN E.M.T ASKED SAME QUESTION I KNEE I HAD IT ON BUT COULDN'T REMEMBER TAKING IT OFF, AND I TOLD HIM THAT. HE LOOKED AT CHEST DIDN'T SEE MARKS OR BRUISING, HE ASKED AGAIN IF I WAS SURE, I WAS SURE I PUT IT ON. AFTER CRASH, WHEN GOT TO TOW YARD NEXT DAY SAW MY SEAT BELT BROKE, I CRACKED THE WINDSHIELD WITH MY HEAD AND BROKE ALL UNDER STEERING WHEEL WITH MY KNEES...BUT THE AIRBAGS DEPLOYED MUST HAVE BEEN AFTER I HIT EVERYTHING BECAUSE IT HIT ME IN THE ARM ONLY BASED ON THAT STINGING RED RAISED RASH THAT LATER BRUISED ON MY FOREARM, NO AIRBAG TO FACE INJURIES, JUST HIT TOP OF HEAD ON WINDSHIELD AND KNEES ON LOWER DASH UNDER STEERING WHEEL, BRUISING ON STOMACH LOWER ABDOMEN NEAR PELVIC BON