OC Transpo bus drivers are warning that problems with scheduling, a bus driver shortage and an influx of students and others heading back to work will cause major headaches for public transit users next week.

A document obtained by CTV Ottawa from the Amalgamated Transit Union shows 680 bus trips have been cancelled and not backfilled this week, leaving transit users stuck waiting at the curb.

"There was only one bus at St. Laurent and it was so full and everyone was in it. And I had to wait and I came late to school," said student Hagar Lakhtar, whose bus didn't show up Friday morning.

The union says this week's problem is nothing compared to what they expect to see next week.

Bus drivers say if the city doesn't take action soon, the number of cancelled trips could double for the busy back-to-school and back-to-work rush.

City council advised of missed trips

A memo from OC Transpo management to city council admitted the number of buses on the road this week fell short, particularly with students in the French language school board returning to class.

"This is obviously a very, very important priority. It should've been a priority last week with the French school board going back," said Mayor Larry O'Brien.

Next week, thousands of students from the Ottawa-Carleton District School Board will return to class, and OC Transpo's general manager says he doesn't expect a problem.

"All bus service is operating normally for the students across the city. Next week, the English school board services will be implemented and running on schedule," Alain Mercier told CTV Ottawa on Friday.

Next week could be worse

However, the Amalgamated Transit Union disagrees. It says even if OC Transpo adds more buses, there simply aren't enough drivers to drive them.

"There's more trips to be covered because of the school going out and more workers going to the office, so I think it will be a big problem," said union spokesperson Yogi Sharma.

With a report from CTV Ottawa's John Hua