I WAS DRIVING WESTBOUND ON I-90W COMING FROM BOSTON WHEN A MILK TRUCK 2 CARS IN FRONT SLAMMED ON HIS BRAKES. TRAFFIC WAS NORMAL AT 4 PM EST. CARS WERE TRAVELING 40-45 MPH AS WE WERE ABOUT 1 MILES OUT OF THE ALLSTON/BRIGHTON TOLLS. I SLAMMED ON MY BRAKES, BUT THE CAR SLID FOR A LITTLE WHILE BEFORE HITTING THE CAR IN FRONT. THE LEXUS RX350 SEEMED TO HAVE VERY SOFT BRAKES, SOMETIMES REQUIRING ALMOST FLOORING OF THE BRAKES BEFORE THE BRAKE CATCHES. THIS IS ESPECIALLY WORSE WHEN THE CAR IS COMING DOWN AN INCLINE, EVEN MODERATE ONES. I'VE REQUESTED A CHECK OF THE BRAKES EVERY TIME THE CAR WAS BROUGHT IN FOR THE 5K SERVICE. BRAKE PADS WERE REPLACED AT 30,000 MILES SERVICE, SO THE BRAKES SHOULD BE NEW. *TR