The days of free parking at GO Transit stations could be numbered.

Metrolinx, the provincial agency that oversees regional transit planning in the GTA, is looking to boost revenue and one possible tool is charging for parking.

Metrolinx president and CEO Bruce McCuaig spoke after a board meeting yesterday.

"It's something that we’re looking at," he said. "It’s something that we want to get input from the public and municipalities and stakeholders on. We need to be able to see how it could have a place and if it doesn’t have a place, why not?"

McCuaig said similar transit systems charge for parking, and the agency needs money.

But many GO Transit riders said they were already charging more than enough for fares.

"I don't think it's fair," a rider at Clarkson station told CBC News on Friday morning. "We already pay enough money on the fare, why would they want to charge us for the parking?"

Another person who commutes into Toronto said a parking charge was "ridiculous."

"It costs me $17/day for @GOtransit," said Margaret on Twitter. "There's a time savings but if costs keep going up we'll move back to T.O.!"

McCuaig said he realizes that by charging for parking, riders will expect better service.

"I think people would say if you’re asking me to pay more … I want to see an improved service as a result of that."

GO currently only charges for reserved parking spots. It owns more than 6,500 parking spots across the GTA.

The TTC makes about $10 million annually by charging for parking.