The union is telling drivers not to book their shifts for May and June until scheduling is discussed.

Transport Minister John Baird proposed Wednesday that federal work-rest regulations be amended to include bus drivers.

OC Transpo drivers have been back behind the wheel of Ottawa buses for several weeks now after a 53-day strike, but the dispute over their schedules has continued.

Alain Mercier, the head of OC Transpo, clashed with the union Tuesday over federal scheduling rules he said the transportation service has to follow.

"It is our obligation to protect the public and our employees, in spite of what they may wish, where the union may wish to take another course of action," said Mercier.

Mercier said he wants drivers to adhere to the federal rules, which means drivers can only work a maximum of 14 hours in a day if they take an eight-hour break.

Without Baird's proposed amendment, however, those rules don't yet include bus drivers.

According to a release from Baird's office, federally regulated transit authorities have been exempt from those regulations since 1989.

The union and drivers, however, say they don't want to be included in the regulations. They say that some of their shifts last longer than 14 hours, and they like them that way. They also say that OC Transpo relies on them to work overtime to cover all of the bus routes.

According to Baird, keeping the buses running shouldn't be the only concern.

"Transit operators must be rested and alert — for the safety of motorists, pedestrians and cyclists who share the road," Baird said in the release. "This new amendment makes work-rest rules mandatory and will make our roads safer."

Ottawa drivers maintain that the way they're working isn't putting the public at risk.

Baird's amendment to the Commercial Vehicle Drivers Hours of Service Regulations would change the scheduling rules for OC Transpo drivers, Société de transport de l'Outaouais (STO) and Transit Windsor.

It's an issue drivers hoped would be worked out through binding arbitration.

Alain Mercier, head of OC Transpo, says drivers should follow federal labour rules. (CBC)

Ottawa's transit strike wrapped up at the end of January only after the arbitration agreement was made.

"Now, correct me if I'm wrong … the whole idea was that everything went to arbitration," said Jim Smith, who's been a driver for 28 years. "And everything means everything."

Although Mercier said that drivers agreed last summer to follow federal rules, the union said that OC Transpo wasn't enforcing them.

"In the past, our drivers were allowed to book up to 22 hours straight and then have a couple hours rest and then back to work," said Jim Haddad, the secretary treasurer with the union. "We said that's not proper."

Haddad also denied that the union ever agreed to follow the federal scheduling standards.

If Baird's proposal goes through, they might have to do just that.

The arbitrator is supposed to meet with the union next month.

In the meantime, the Amalgamated Transit Union has been telling its workers not to agree to take on shifts for May and June.

Drivers book their shifts four times a year and now is the time when scheduling would normally be done for those two months.

"Change the legislation and we'll abide by the legislation," says André Cornellier, the head of the transit union. "But until you change the legislation why implement something that we're going to [discuss through] arbitration?

"The minister is supposed to be looking into this situation," he said.