By David Shepardson and Ian Simpson
WASHINGTON (Reuters) - A Baltimore school bus involved in a crash last month that killed six people was traveling at almost twice the speed limit and its driver had a history of seizures, federal investigators said on Wednesday.
The school bus, which had no students aboard, was traveling at about 57 miles per hour when it rear-ended a Ford Mustang in an area with a posted speed of 30 mph on Nov. 1, the National Transportation Safety Board said in a preliminary report.
The bus, operated by a contractor for Baltimore City Schools, crossed the road's center line and smashed into an oncoming commuter bus. Six people, including school bus driver Glenn Chappell, 67, were killed, and 11 people were injured.
The other people killed were the driver of the commuter bus and four transit passengers.
The NTSB report said Chappell had a history of hypertension, diabetes and seizures. He had been involved in at least 12 crashes or incidents in the previous five years, and reports from some cases described seizure-like episodes, it said.
Paramedics had been called to the school bus company, AA Affordable Transportation in Baltimore, the week before the crash because Chappell was experiencing what witnesses described as a seizure.
After the school bus hit the Mustang, a teacher's aide who was aboard asked Chappell what had happened, but he did not respond, the report said.
The NTSB said Chappell held a current medical certificate to drive but it was not on file with the Maryland Motor Vehicle Administration. About two months before the crash, the agency told the school bus driver that he was no longer authorized to operate a commercial motor vehicle.
AA Affordable had contracts to run seven Baltimore City school bus routes and three Howard County school bus routes.
Chappell had been driving for various school bus companies since 2008.
Neither driver was using a cell phone, and there was no sign of mechanical malfunction, the report said.
(Editing by Leslie Adler)