I WAS DRIVING NORTHBOUND ON I-435 WHEN AVOIDING AN ACCIDENT. I PRESSED MY BRAKE AS HARD AS I COULD. MY VEHICLE DID NOT STOP SO TO AVOID CAUSING A SERIOUS ACCIDENT I WENT OFF ROAD IN THE CENTER OF THE TWO HIGHWAYS. AFTER HITTING THE GUARDRAIL TO STOP MY VEHICLE FROM FALLING INBETWEEN THE OVERPASS. MY AIRBAGS DID NOT DEPLOY . I FEEL SOME CONCERN AFTER HAVING MY BREAKS CHECKED AND TOLD THEY WERE GOOD. THEN IF I'M AT STOP AND I RELEASE THE BREAK FOR MY CAR TO START BACK UP. I GIVE IT A SECOND AND THEN PRESS THE PEDDLE IT DOES NOT MOVE WHICH HAS ALMOST CAUSED ME TO HOLD UP TRAFFIC OR ALMOST BEING HIT WHEN VEHICLES WERE AT SAFE DISTANCES.