AFTER EXITING THE OFF RAMP OF I264 IN PORTSMOUTH, VIRGINIA I SPED UP TO APPROXIMATELY 35 MPH AND APPROACHED THE NEXT STOP LIGHT. UPON APPLYING PRESSURE TO THE BRAKE PEDAL NO RESISTANCE WAS NOTED AND THE SLOWING OF THE VEHICLE WAS FOUND NEGLIGIBLE. I REAR ENDED A VEHICLE IN FRONT OF ME AT APPROXIMATELY 25 MPH. BOTH CARS INVOLVED IN THE ACCIDENT WERE PULLED INTO THE MEDIAN OUT OF TRAFFIC. AS I EXITED THE VEHICLE I NOTICED FLUID DRIPPING FROM THE TRUCK FRAME AT THE FORWARD HINGE OF THE DRIVER SIDE DOOR. THE DRIPPING FLUID WAS BRAKE FLUID. I SUSPECT A RUPTURED BRAKE FLUID LINE OR TUBE HAD RUPTURED WHICH CAUSED THE LOSS OF BRAKING POWER. THERE WAS NO WARNING GIVEN BY THE VEHICLE'S COMPUTER TO WARN OF LOW BRAKE FLUID BECAUSE THE RESERVOIR WAS STILL AT THE NORMAL LEVEL. I BELIEVE CORROSION OF THE BRAKE LINES WAS ACCELERATED DUE TO THE USE OF SALT TREATMENTS ON THE ROADS DURING THE WINTER SNOW STORMS THAT HAVE FALLEN IN THE PAST THREE YEARS. LUCKILY NOBODY WAS SERIOUSLY HURT AND LUCKILY THIS DID NOT HAPPEN WHEN I WAS EXITING THE INTERSTATE AT A MUCH HIGHER RATE OF SPEED. ALSO THE AIR BAG DID NOT DEPLOY UPON IMPACT. THESE ARE TWO SERIOUS SAFETY ISSUES INCURRED IN ONCE INCIDENT TO A TRUCK WHICH HAS LESS THAN 70K MILES AND 12 YEARS OLD. *TR