VEHICLE WOULD NOT STOP WHEN FOOT BRAKE WAS APPLIED. WHEN BRAKE WAS APPLIED VEHICLE LUNGED FORWARD. DRIVING ON A MAIN ROAD, PASSING THROUGH A SCHOOL ZONE AND APPROACHING A STOP LIGHT. THIS WAS THE SECOND TIME VEHICLE WOULD NOT STOP IN THE PAST TWO MONTHS. I HIT THE REAR OF ANOTHER VEHICLE DAMAGE OCCURED.