Published: May 07, 2010 4:26 PM EDT

LOUISVILLE, Ky. - Kentucky State Police say a truck driver had no drugs or alcohol in his system when his rig crossed an interstate median and smashed into a family's van, killing 11 people.

Kentucky State Police Trooper Charles Swiney told The Courier-Journal in Louisville that toxicology tests on driver Kenneth E. Laymon were negative.

The 45-year-old from Alabama had been sending and receiving calls from his cell phone leading up to the March 26 crash, according to a Kentucky State Police report.

Laymon was among those killed in the wreck. Peter Knudson, a spokesman for the National Transportation Safety Board, says the agency hasn't yet verified whether Laymon was talking on his phone when the truck ran off the central Kentucky highway.