I WAS TRAVELING ON I-95 NORTH BOUND IN SOUTH CAROLINA AT 75 MPH IN THE FAR LEFT LANE. I WENT TO SHIFT BACK TO THE CENTER LANE WHEN THE POWER STEERING COMPLETELY FAILED AND SENT US ACROSS 3 LANES OF TRAFFIC. WE ALMOST SIDESWIPED A SEMI-TRUCK. I WAS ABLE TO BREAK ENOUGH TO END UP BEHIND THAT TRUCK IN THE FAR RIGHT LANE AND REGAIN CONTROL OF THE VEHICLE. THE RED STEERING WHEEL LIGHT WAS ILLUMINATED ON THE DASH BOARD WITH A MESSAGE POWER STEERING FAILURE SERVICE REQUIRED. I WAS ABLE TO MAKE IT TO THE NEXT OFF RAMP AND ONCE ABOUT HALF WAY UP THE RAMP THE POWER STEERING STARTED WORKING AGAIN. SEVERAL HOURS LATER THE POWER STEERING WENT OUT AGAIN THIS TIME I WAS GOING STRAIGHT AT 65 MPH IN NORTH CAROLINA. IT REMAINED OUT FOR A FEW MINUTES AND THEN STARTED WORKING AGAIN. IT DID THIS 4 MORE TIME ON OUR TRIP FROM FLORIDA TO MARYLAND. ON ONE OCCASION WE WERE IN TRAFFIC IN VIRGINIA AT 5 MPH AND IT WENT OUT FOR ABOUT 10 MINUTES BEFORE WORKING AGAIN.