MILFORD, Conn. – A Littleton man was critically injured Thursday evening when he was hit by a rock thrown by a person while he was driving a tractor-trailer on Interstate 95 in Milford, Conn.

Wayne Tapley, 48, was reported to be in good condition Monday afternoon at a Connecticut hospital. Tapley’s family from Maine was with him, according to hospital officials.

“Mr. Tapley was transferred out of the surgical intensive care unit over the weekend,” Mark D’Antonio, spokesman for Yale New Haven Hospital in New Haven, Conn., said Monday. “His nurses had him up and walking, so we are very optimistic. … This is a good sign.”

Tapley was northbound in his tractor-trailer at about 8:30 p.m. Thursday when he was struck by a rock that came through his windshield, police said.

They think the truck driver may have been dazed or knocked unconscious by the rock, causing him to lose control of the vehicle and sideswipe a tour bus.

There were 45 people on the tour bus. Two passengers were injured, but their injuries were not considered to be life-threatening, according to police.

Tapley was driving a tractor-trailer, owned by James Westerdahl of Littleton, filled with tomatoes.

Connecticut State Police from Troop G in Bridgeport initially were called to the accident scene after several motorists reported rocks being thrown onto the interstate near Exit 35 on the northbound side near Milford.

Moments later, callers alerted 911 dispatchers to the accident involving the tractor-trailer and the tour bus in the same vicinity. Upon arriving at the scene, police discovered the tractor-trailer down an embankment.

Police and fire officials reported that after Tapley was hit by the rock, his truck careened off the median barrier, swerved back across the highway and plunged down a steep embankment.

Tapley had to be extricated from the vehicle and was taken by ambulance to Yale New Haven Hospital, where he was listed in critical condition on Friday.

State police have initiated an investigation into this crash and also are conducting four criminal investigations into other incidents that occurred in the same area.

“State police are also investigating damage that rock throwers in the same area of the crash did to three other vehicles,” Trooper 1st Class Karen O’Connor, spokeswoman for the Connecticut Department of Public Safety, said Monday. “We did not have success in finding the assailant or assailants, but we did develop some information in the case.”

Westerdahl said Monday that Tapley has been driving for him for 12 years without incident.

“He is a great person, very family-oriented and has been basically driving a truck all of his life,” Westerdahl said. “He’s the type of person who will do anything for you.”

Tapley’s wife, Nicole, his daughter and his mother are with him at the hospital.