I WAS DRIVING BETWEEN 40-45 MPH COMING TO AN INTERSECTION. TRAFFIC LIGHT WAS RED AND SOME CARS WAITING. I TOOK MY FOOT OFF THE ACCELERATOR AND PUT IT ON THE BRAKE PEDAL WHILE APPROACHING THE STOPPED TRAFFIC. I TRIED TO BRAKE BUT THE PEDAL WENT SOFT TO THE FLOOR. I WAS DRIVING A 2008 CADILLAC DTS , AND I HIT THE CAR STOPPED IN FRONT OF ME. THERE WAS A FAILURE IN THE BRAKING SYSTEM. MY CAR HAS ABOUT 5,000 MILES ON THE ODOMETER. I AM REPORTING THIS TO MY CADILLAC DEALER ON MON 22 OF FEB, 2010. THE AIR BAG DID NOT DEPLOY. NO KNOWN INJURIES TO OCCUPANTS OF THE OTHER CAR. I SUSTAINED HIGH BLOOD PRESSURE AND WAS TAKEN BY AMBULANCE TO WELLSTAR COBB HOSPITAL EMR. I RETURNED HOME THAT AFTERNOON, BUT THE NEXT MORNING I HAVE SORENESS IN NECK AND CHEST. *TR