Multiple vehicles were involved in a crash Wednesday in Plainfield, State Police said.
The crash happened in the northbound lanes, police said.
According to State Police, the squad car was stationary in the left lane with its emergency lights while assisting a stalled motorist.
A vehicle was traveling northbound and rear ended the state trooper's squad car, causing a multi-car crash.
In addition to the state trooper, two other drivers were also taken to a hospital, both with injuries that are not life threatening, police said.
The northbound lanes were reopened approximately three hours after the crash.