THE GMC VAN WAS WEST BOUND ON HWY 67 AND WAS AT A STOP YIELDING FOR TRAFFIC TURNING ONTO CR 209. THE OTHER VEHICLE ALSO WEST BOUND WAS NOT PAYING ANY ATTENTION TO THE ROAD WHILE HAVING HER HEAD DOWN LOOKING ON THE FLOOR BOARD AND DID NOT SEE THE VAN STOPPED AND REARENDED IT. SHE WAS TRAVELING AT 60 MPH AND NEVER APPLIED HER BRAKES. UPON IMPACT THE DRIVER'S SEAT BROKE COMPLETELY AND WHEN THE DRIVER CAME TO HE WAS LAID OUT FLAT IN THE SEAT ON THE FLOOR BOARD LOOKING UP AT THE CEILING. THE PASSENGER SUSTAINED SEVERE BACK INJURIES FROM THE SEAT BREAKAGE THAT BANGED INTO HIS BACK. *AK