UNMARKED POLICE CROWN VICTORIA SEDAN TRAVELING IN LEFT LANE OF 4-LANE, GRASS MEDIAN-SEPARATED HIGHWAY WITH POSTED SPEED LIMIT 55 MPH. POLICE OFFICER DRIVER DECEASED IN CRASH. WITNESSES REPORT: AFTER ENTERING HIGHWAY, VEHICLE ACCELERATED TO HIGH RATE OF SPEED; IN VICINITY POLICE MEDIAN TURNAROUND, POLICE STROBE LIGHTS WENT ON; VEHICLE STARTED WOBBLING AND MOVING GRADUALLY TO LEFT IN STRAIGHT PATH. EVENT DATA RECORDER INDICATED BRAKES APPLIED AND VEHICLE SLOWED BEFORE COLLIDING WITH CONCRETE BRIDGE UNDERPASS ABUTMENT. SMALL GRASS FIRE EXTINGUISHED AROUND FRONT-END OF VEHICLE. CURSORY VEHICLE EXAMINATION ON 09/15/11 REPORTS: AIRBAG DEPLOYED, SEAT BELT LOCKED UP DUE TO IMPACT, UNABLE TO CHECK BRAKE PEDAL, UNABLE TO CHECK FRONT BRAKES, AND BAD STEERING (NO FURTHER DETAILS ON CONDITION STEERING PARTS). *TR