California Highway Patrol Officer Vincent Smith remained in serious condition Sunday after being hit by a FedEx truck while trying to clear the roadway of two other vehicles involved in a hit-and-run crash, reports the Sacramento Bee .

Smith, an 18-year veteran, responded with other officers to a two-vehicle crash on Highway 50 near 16th Street in Sacramento just after 3 a.m. Saturday, according to CHP spokesman Officer Michael Bradley. One driver involved in the crash had fled on foot, and both vehicles remained in the roadway, Bradley said. The officers activated their overhead patrol lights and were working to move the vehicles onto the highway’s shoulder.

Before they could finish clearing the roadway, Smith was hit by a FedEx tractor-trailor driven by Gregory Anthony Ramirez, 41, of San Lorenzo, Bradley said. Ramirez was taken to the CHP’s south Sacramento station for evaluation and subsequently was arrested on suspicion of felony driving under the influence causing injury and illegal drug possession.

Smith suffered major injuries to his upper body, Bradley said, and remains in serious but stable condition. The CHP would not identify the hospital where he is being treated. Bradley said Smith has been surrounded by family members and that officers were taking shifts to stand watch at his room.