Updated

Surgery on Gov. Jon S. Corzine's injured leg was successful Saturday, while state police said the driver blamed for the wreck that critically injured the governor had been found but didn't realize he was involved.

Corzine's recovery was progressing better than doctors expected, said Dr. Steven Ross, head of trauma at Cooper University Hospital. Doctors cleaned a 6-inch wound during surgery on his left thigh.

The governor is not able to speak and not aware of his surroundings because of his heavy sedation. He is expected to remain on a ventilator until at least Monday, doctors said.

"He awakens, answers to simple 'yes or no' questions about pain," Ross said. "He won't remember much of what is going on at this point."

Corzine was hurt Thursday when the SUV he was riding in was clipped by a vehicle that swerved to avoid a red pickup truck that officials said was being driven erratically. Corzine's vehicle slammed into a guard rail along the Garden State Parkway in Galloway Township, near Atlantic City.

The 20-year-old driver of the red truck was found Friday night at an Atlantic City casino where he works and interviewed by police, police said.

He wasn't charged with leaving the scene of an accident because he didn't realize he was involved in the crash, State Police Capt. Al Della Fave said. However, authorities left the door open for charges to be filed later, saying the investigation was not yet complete.

The driver of the truck picked it up Saturday afternoon at the New Jersey State Police station in Buena Vista. He did not talk to the media.

An official with knowledge of the investigation described the driver as a "special needs driver," but said it was unclear if that contributed to the accident. The official spoke also on the condition of anonymity because that official was not authorized to discuss the matter.

The driver apparently thought he had avoided an accident because his truck never came in contact with other vehicles, police said.

"He hadn't any inkling that he contributed to it (the accident)," Della Fave said. "That alleviates him of the responsibility of remaining at the accident scene."

The driver was tracked down in part using leads from Garden State Parkway surveillance cameras and toll information, police said.

Corzine — who was riding in a sport utility vehicle driven by a state trooper and headed to a meeting between radio show host Don Imus and the Rutgers women's basketball team — apparently was not wearing his seat belt, as required by law.

Also, a governor's spokesman said he didn't believe the air bags in the SUV deployed.

The governor's femur bone was broken in two places, and it protruded through his skin. He also suffered a broken sternum, 12 broken ribs, a head laceration and a minor fracture on a lower vertebra, according to doctors at Cooper University Hospital in Camden, where he was flown by helicopter after the crash. Corzine, 60, did not appear to suffer any brain damage.

His injuries were not considered life-threatening, but doctors say the governor faces lengthy rehabilitation. And it will likely be at least three to six months before he can walk normally.

A similar surgery to clean out Corzine's femur was planned again Monday, Dr. Robert F. Ostrum said.

Tom Shea, the governor's chief of staff, said he was hopeful Corzine could resume his duties in "a week or so," depending on doctor recommendations. Shea said it was possible Corzine would govern from his hospital bed.

Corzine was moved to the trauma intensive care unit after surgery Thursday night and remained in critical but stable condition Saturday.

Senate President Richard Codey officially became acting governor Thursday evening after getting a fax from Corzine's office saying the governor had been injured.