By Robin Rieger

PITTSGROVE, N.J. (CBS) — A 37-year-old father and his five-year-old son were killed after their car collided head-on with a tractor-trailer on Route 40 in Pittsgrove Township, Salem County early Wednesday morning.

According to investigators, 37-year-old Kevin Shelton was driving westbound on Route 40 when his Grand Prix crossed into the eastbound lanes and into the path of the tractor-trailer.

Shelton and his five-year-old son, Cole, were killed in the crash. Shelton’s three-year-old daughter Cassidy was flown to Cooper University Hospital, where she was upgraded from critical to stable condition.

“The children are beautiful, beautiful children. Good little kids,” said family friend Jane Williams.

She says Shelton was taking his children to their babysitter on Wednesday morning.

State police say they don’t know if Shelton was distracted or if the two child seats in his car were being used properly.

“At this point, it appears the Pontiac went into the eastbound lane, causing the collision. We’re taking statements from the tractor trailer driver–looks like he was trying to get out of the way,” said New Jersey State Trooper Jason Pasqua.

The driver of the tractor-trailer, 47-year-old Robert Peck of Chattanooga, Tennessee was not injured. He declined to speak, but witnesses say that he was crying at the crime scene.

“He just said the guy kept coming over and over in his lane; there was nothing he could do,” said Harrison Godshall, who heard the crash and also said he heard a little girl crying at the scene.

Williams, who runs a local hardware store, says Shelton lived with his parents and his children after their mother, his girlfriend, suffered an aneurysm and could no longer care for them.

“That was his life, his two children really…it’s so sad,” Williams said.

Peck’s truck was hauling a load of paper. Authorities say he is not being looked at as being at fault.

The accident remains under investigation.