ON OCTOBER 4, 2017 AT APPROXIMATELY 3:45 PM, I DEPARTED FROM THE SACRAMENTO CHILDREN'S HOME THROUGH AN ADJACENT ALLEY TRAVELING THROUGH THE SOUTH BOUND ENTRANCE. AS I MADE THE LEFT TURN INTO THE ALLEY AS I GRADUALLY GOT UP TO SPEED MY VEHICLE SUDDENLY BEGAN TO ACCELERATE. I WAS STARTLED BY THE SUDDEN INCREASE OF SPEED AND IMMEDIATE MADE AN ATTEMPT TO PUT THE VEHICLE IN NEUTRAL AND SHUT THE VEHICLE DOWN AND APPLY THE BRAKES. BEFORE I COULD MAKE THE CORRECTIONS THE VEHICLE HAD VEERED OFF TO THE LEFT HAND SIDE OF THE ALLEY AND STRUCK AN OAK TREE. TO MY GUESS THE VEHICLE WAS TRAVELING AT A RATE OF SPEED OF ABOUT 25-30 MPH. ON IMPACT I SLAMMED INTO MY MOTOROLA SPEAKER THAT WAS ATTACHED TO MY SUN VISOR AND SPLIT MY HEAD OPEN WHICH REQUIRED 8 STAPLES TO CLOSE.