Bus driver scheduling is causing tensions to flare as the City of Ottawa moves forward with a new scheduling plan that adheres to federal safety rules that will force bus drivers to take an eight-hour mandatory rest period between shifts.

Although the scheduling issue was supposed to be resolved through binding arbitration, federal Transport Minister John Baird says he's ready to step in and introduce regulations that would put limits on the number of hours worked by OC Transpo drivers.

New rules would limit drivers to 14 hours of work in one day with at least eight hours between shifts. Under the current system, drivers can work as much as 22 hours in one day.

"It is clearly and without a doubt a safety issue," Mayor Larry O'Brien told reporters on Wednesday.

Although the mayor says he's thrilled with Baird's decision, union officials say they're furious about the change to the current scheduling system, which was a major sticking point in a public transit strike that lasted for more than 50 days.

The union says it learned of the change when OC Transpo general manager Alain Mercier called an emergency meeting Tuesday night.

Although the mayor says he understands the two sides had a discussion about the issue, union officials say the decision was more of a "take it or leave it" situation.

"Never, never did Alain Mercier ever even suggested that we be involved in how we could implement some safety measures," said Andr� Cornellier, president of ATU local 279.

While the city maintains scheduling needs to be changed to address safety concerns, Cornellier argues city officials have no evidence to prove drivers who work long hours put the public's safety at risk.

"I don't see it as an issue. They have no facts, they have nothing to report any suggestion that driver fatigue has caused any accidents or anything at OC Transpo and we've been doing this forever," Cornellier told CTV Ottawa.

In the meantime, the union is urging bus drivers not to book spring shifts to protest the new scheduling restrictions. Instead the previous schedule will be repeated.

"If (Baird)'s going to legislate the hours, then we'll have to obey the regulation as far as the law. But right now there's no legislation, there's no law," Cornellier said.

Both the city and the union say the scheduling dispute won't disrupt OC Transpo service, which will continue as usual.

With a report from CTV Ottawa's Natalie Pierosara