Wichita ? Driver fatigue is linked to at least one of three deadly crashes over a two-month period in a construction zone on U.S. Highway 50, and the Kansas Highway Patrol says the other two may also have been caused by sleepy truck drivers.

Between May 10 and June 29, nine people were killed in three crashes involving semitrailers that plowed into other vehicles that had stopped or slowed for construction work near Peabody. The Wichita Eagle on Thursday obtained the final Highway Patrol reports for the May 10 and June 28 accidents. A final report on the June 29 crash in which five people were killed has not been released.

A witness to the May 10 crash, which killed two women, said the truck driver who struck a van from behind told the witness he had “fallen asleep at the wheel and woke up after hitting the van,” the patrol said.

The report says that witness helped pull the 62-year-old truck driver from Emporia from his overturned vehicle before it exploded.

The truck driver told an investigator at the hospital that he took drugs for diabetes and high blood pressure, the report said.

“I asked him if he was feeling good today, and he stated, ‘I didn’t feel real good, but as a diabetic, you have a lot of days you don’t feel real good,”‘ the investigator wrote in the report.

In the June 28 crash, a truck driver whose rig plowed into the back of a pickup truck told a patrolman that he had seen signs warning of the construction zone, but he didn’t remember what they said.

Two men in the pickup truck were killed after their vehicle burst into flames and was pushed under the trailer of another truck.

The report said road workers tried desperately to pull the two men from the burning pickup, using fire extinguishers and throwing ice and water from coolers onto the burning cab before the fire became so big they had to back off.

The 51-year-old truck driver was pulling an empty trailer and had his cruise control set on 64 mph, the patrol report said. One witness whose car also was hit from behind by the semitrailer told troopers that he didn’t see the truck slow down.

The report said there were no signs that the truck driver was impaired.

Based on evidence at the scene of the June 28 and June 29 crashes, the patrol said, both drivers could have been sleepy. The Kansas Department of Transportation has said there was no indication that the construction zone was not appropriately marked.

Still, the Highway Patrol has increased enforcement in the area since the June 29 accident, and additional warnings, including diverting drivers onto a shoulder rumble strip, have been installed.