EE WAS DRIVING A 1978 WABCO WATER TRUCK AND WAS UNABLE TO STOP WHEN THE ENGINE QUIT. THE UNIT TRAVELED 300 FEET AND STOPPED ON A BERM. THE WATER SHIFTED AND THE TRUCK ROLLED 3/4. EE RECEIVED 4 BROKEN AND 3 CRACKED RIBS. (EE WAS NOT THROWN FROM VEHICLE.)