ON DEC 11, 2009, I WAS DRIVING DOWN A STREET IN CAMBRIDGE, MA (I HAD A COWORKER IN THE CAR) AND WE WERE IN STOP AND GO TRAFFIC AT A STOP LIGHT. THE CAR IN FRONT OF ME CRAWLED UP TO APPROACH THE LIGHT AFTER SEVERAL CARS HAD GONE THROUGH-THEN STOPPED @ THE RED LIGHT. I PROCEEDED TO DO THE SAME. WHEN I APPLIED MY BRAKES TO STOP THERE WAS NO RESPONSE, SO I PRESSED DOWN HARDER-STILL NO RESPONSE. I THEN BEGAN TO PUMP MY BRAKES TO AVOID THE ACCIDENT BUT THERE WAS STILL NO RESPONSE FROM THE BRAKING SYSTEM. IF THE BRAKING SYSTEM HAD NOT FAILED I WOULD HAVE MORE THAN ENOUGH RESPONSE TIME AND DISTANCE TO STOP BUT MY CAR KEPT @ A STEADY SPEED AND ENDED UP REAR ENDING THE CAR IN FRONT OF ME. NO ONE WAS INJURED BUT THERE WAS MINOR DAMAGE TO THE CAR IN FRONT OF ME AND $1800 DAMAGE TO MY CAR. I'VE HAD OTHER INSTANCE WHERE I'VE HIT POTHOLES IN THE PAST WHILE SLOWING DOWN- AND THE BRAKE SYSTEM WOULD STOP MOMENTARILY FROM WORKING. I WORK IN THE BOSTON AREA- WHERE I'M CONSTANTLY IN STOP AND GO TRAFFIC. I'VE EXPERIENCED 2 PREVIOUS TIMES SLIGHT BRAKE DELAY-WHICH I'VE COMPENSATED FOR AND GIVE MYSELF MORE ROOM BETWEEN MY CAR AND THE CAR IN FRONT OF ME. IN ADDITION THERE WAS ONE INSTANCE 4MONTHS AGO WHERE I WAS COMING TO A STOP- AND I HEARD ONE OF THE MOTORS (I'M ASSUMING THE ELECTRIC B/C IT CHARGES AS YOU STOP) REV UP AND MY CAR JILTED FORWARD- AS IF I HAD STEPPED ON THE GAS BUT I HAD MY FOOT ON THE BRAKE THE WHOLE TIME. THAT WAS THE ONLY INSTANCE OF THAT. I'VE HAD MY CAR SINCE APRIL 2009 AND WHEN