DALLAS -- Dallas County Schools, the bus operator for Dallas ISD, has fired 13 bus drivers, demoted two executive directors, and suspended 229 other drivers for red light or stop arm violations on the job.

In a news release, Dallas County Schools said an internal investigation was launched after a local report raised questions and DCS found 483 citation records from January 2014 to September 2016 involving a total of 242 of its drivers. More than 60 percent of the citations were for red-light tickets.

The drivers who were fired all had three or more red light or stop arm violations in the last two years.

“They found it, we owned it and we fixed it,” said Larry Duncan, board president for Dallas County Schools. “There were multiple failures at all levels because staff didn’t follow procedures and there was no oversight on this issue. However, moving forward, one accountant is responsible to review, follow-up, and make sure that every ticket is paid and every driver pays it back.”

Duncan also said the DCS Policy Committee approved a new policy on driver violations on Tuesday that includes a first-offense termination provision for its drivers who are found to have committed a stop-arm violation.

“This is a one-and-done offense,” Duncan said. “Drivers know better and we will not tolerate stop arm violations from our own employees.”

Additionally, the bus operator said their policy includes language saying drivers must report a criminal charge, traffic violation, or arrest within 24 hours and that failure to make that report would result in termination.

DCS plans to stagger the employees' suspensions to avoid any disruption in bus routes.

Dallas County Schools’ investigation is ongoing, the release said, and more disciplinary action may result from the continued investigation.