A driver who apparently took her work rules very seriously abandoned a bus full of former prisoners along a highway because her hours for the day were over, police said.

The 40 passengers had been paroled or released from the state prison in Huntsville. Some wore ankle bracelet monitors.

They were aboard a charter bus that was headed Thursday to a terminal in Dallas but wound up 60 miles short.

"In 31 years in law enforcement I've never seen anything like this," Corsicana Police Sgt. Lamoin Lawhon said.

Police said the bus was chartered from Greyhound Bus Lines Inc. The driver pulled over in front of a convenience store around 4 p.m. and told the passengers her allotted driving time was up and another driver was on the way.

A clerk in the convenience store called police. Officers arrived to find the former prisoners milling around the bus. Dispatchers exchanged several phone calls with Greyhound and prison officials while Lawhon and two other officers stayed with the bus and the passengers.

Just before 7 p.m., a second bus arrived with three drivers -- including the one who had abandoned her passengers in the first place, Lawhon said.

Greyhound spokesman Dustin Clark said company officials were investigating the incident. "It is a very serious matter," he said.

Clark said drivers have to follow strict guidelines on consecutive working hours and rest periods.

Police said there were no incidents involving the passengers while they were stranded.

"Their behavior was exemplary," Officer Travis Wallace said.