HAD DELIVERED A BUSLOAD OF STUDENTS TO LUNCH AND PICKED UP ANOTHER IMMEDIATELY BUSLOAD (44 PASSENGERS) THEREAFTER. UPON TOPPING A STEEP HILL BRAKES DID NOT SEEM TO BE FUNCTIONING PROPERLY. PULLED EMERGENCY BRAKE BUT DDID NOT STOP IN TIME TO AVOID COLLISION WITH ANOTHER TRANSIT BUS, INJURING 18 (IINCLUDING MYSELF) SLIGHTLY. I WAS REMOVED FROM THE POSITION AND WRITTEN UP FOR THE ACCIDENT. NOTHING HAS BEEN DONE TO FIX THE BRAKES, AS FAR AS I KNOW. I BELIEVE THE LOAD WAS TOO MUCH FOR THE BRAKE SYSTEM OR THERE WAS A DEFECT IN THE BRAKE SYSTEM CAUSING BRAKING ABILITY TO DIMINISH.*AK