The accident happened about 1 p.m. near the Capitol exit in the southbound lanes of Interstate 5.

Investigators tell KIRO TV News that the trooper had just finished pulling over a Cadillac Escalade and was re-entering traffic when a Toyota pickup smashed into the patrol car -- pushing it under the Escalade. WSP says the 84-year-old driver of the pickup changed lanes just as the trooper pulled onto the freeway.

The pickup driver and his woman passenger were taken to St. Peter's Hospital for treatment. The trooper was treated and released from St. Peter's.

The left lane of southbound I-5 from milepost 104 to milepost 107 was blocked for two hours. The traffic backup stretched into the evening commute.