WHILE DRIVING ON INTERSTATE IN PHOENIX AT NOON ON A DRY AND CLEAR DAY, TRAFFIC STOPPED ABRUPTLY. I REAR-ENDED A FULL SIZED PICKUP TRUCK. THE FRONT END WENT MOSTLY UNDER THE TRUCK, SHATTERED THE UPPER HALF OF THE BUMPER AND HEADLIGHTS, FOLDED THE HOOD IN HALF. THE WINDSHIELD WAS ALSO BROKEN. MY HEAD HIT THE STEERING WHEEL AND NO AIRBAGS WERE DEPLOYED. THE POLICE REPORT ESTIMATED SPEED AT IMPACT TO BE 25 MPH BUT THERE WAS NOT AN EXTENSIVE INVESTIGATION.