Four high-ranking transportation managers are no longer with the city, CBC Toronto has learned.

Barbara Gray, the city's new general manager of transportation, sent a letter to her department late this week to announce the shakeup, sources say.

According to the letter, the four are:

Jacqueline White, the director of transportation services for the North York district.

Hector Moreno, a manager in the Scarborough district who has been listed as a contact on several paving tenders.

Trevor Tenn, a manager in road operations who frequently spoke with the media to get drivers prepared for rough weather.

Bruce Shaw, a maintenance contract inspection supervisor.

Hector Moreno, left, had been a manager in the Scarborough district, while Trevor Tenn, right, was the city's manager in road operations. Both are no longer working with the city. (CBC)

Gray's letter thanked all four for their "significant contribution" to the city and that the change was the result of realigning management. City spokesperson Wynna Brown declined to say why the managers are no longer working at the city.

"We do not discuss personnel matters," she said in a statement.

"I can, however, confirm that there have been some recent management changes in Transportation Services."

CBC Toronto asked seven councillors about the situation, but none commented on the change. Coun. Stephen Holyday, chair of the audit committee, said he has sent some questions about the situation to staff.

Public Works Chair Jaye Robinson's office said she doesn't have any information about the change, either.

Paving contracts subject of auditor general probe

Earlier this year, Toronto's Auditor General Beverly Romeo-Beehler released a report that found potential bid-rigging in the area of paving contracts handed out by the city from 2010-2015.

Ontario Provincial Police are now investigating the situation, which may have cost the city millions, Romeo-Beehler's report says.

Both Gray and City Manager Peter Wallace told the audit committee better systems are now in place, but the city has to keep a close eye on the $100 million worth of road-work contracts it hands out every year.