Toronto Mayor Rob Ford drove past the open doors of a streetcar, resulting in an exchange with the TTC operator, the head of the transit union alleges.

Bob Kinnear, who leads the Amalgamated Transit Union Local 113, told reporters of the incident Friday morning. He said the mayor drove past the rear doors of a streetcar on Dundas Street West near McCaul Street on Wednesday.

"My understanding is that Mr. Ford did pass open doors of a streetcar. And the operator counselled Mr. Ford on the serious safety violation and the potential danger of doing that," Kinnear said.

Driving past the open doors of a streetcar is a violation of the the Highway Traffic Act — one the Toronto Transit Commission says happens hundreds of times a day. Offenders can be fined up to $109.

Kinnear said in this case the driver walked to the bottom of the stairs and words were exchanged.

"My understanding is that [Ford] did roll down his window and had some comments for the operator. I don't know specifically what those comments were," said Kinnear.

It wasn't clear if the mayor drove past open front doors. Kinnear said he only knows that Ford allegedly drove past the rear doors.

"I'm not sure of the specifics of the circumstances, but my understanding is there was an open door passed," Kinnear said.

He added the union does not encourage its members to interact with motorists

"We don't encourage them to leave the seat," he said.

"But ... when you're an operator and you see this numerous times throughout the day, we and our operators are very concerned about public safety and want to ensure that motorists as well as our passengers know the rules and ensure the safety and integrity of the system."

TTC CEO Andy Byford said his office received a call from the mayor about the incident.

"I did speak with the mayor but it wasn't because the mayor was involved," Byford said. "We followed the normal process of investigation that we would regardless of who the complainant was."

The operator was interviewed and has not been disciplined. The TTC now considers the matter closed.

The mayor's office is not commenting.