Michael Mundy was driving to work Friday morning when he noticed a plume of smoke rising from Board Road in Manchester Township.
As he got closer, he noticed the back end of a tractor-trailer was on fire.
He then noticed a motorcycle wedged under the truck and a man lying face down in the roadway about 40 yards away.
"The rider didn't move at all," Mundy said.
A woman had stopped in the middle of the road and was calling 911 for help just before 8 a.m.
Mundy then heard an explosion from what he said he believed was the motorcycle's gas tank.
"There was this boom. Everything kind of shook," Mundy said.
Daniel James Coulson, 29, of York was killed after his motorcycle crashed into a tractor-trailer pulling out of a business in the 3400 block of Board Road, near Church Road, police said.
Coulson was pronounced dead at the scene from multiple blunt force trauma, according to the York County Deputy Coroner Mary Breighner. He was wearing a helmet, she said.
Just before 8 a.m. Friday, a Freightliner truck and trailer pulled onto Board Road and was attempting to go left when it was hit by Coulson's 2003 Suzuki motorcycle, according to Northern York County Regional Police.
Several witnesses said the motorcycle was traveling at a high rate of speed before the crash, Police Chief Carl Segatti said.
The motorcycle was unable to stop before hitting the trailer in front of the rear tandem wheels, Segatti said.
The motorcycle became wedged under the trailer and burst into flames, he said. Coulson was thrown clear of the wreckage.
Since 2000, Coulson had pleaded guilty in York County to eight traffic violations, including twice disregarding traffic signals; twice driving in excess of the maximum speeds by 25 and 29 mph; and careless driving, according to court records.
Before continuing on his way to work, Mundy said he did not know Coulson was dead.
He said he had a bad feeling by the way people left him lying along the road.
Looking at the aftermath, Mundy also had a feeling speed was a factor.
He said the Board and Church roads intersection is relatively safe with good visibility.
Mundy lives in Manchester Township and said he drives through the intersection regularly.
"You can see up and down the road," Mundy said.