TORONTO -- Ontario NDP Leader Andrea Horwath and Liberal Premier Kathleen Wynne touted transit promises Thursday, a day after Doug Ford promised to help drivers by cutting gas prices by 10 cents a litre.

The Progressive Conservative leader said he would cut gas prices by slashing the provincial gas tax by 5.7 cents a litre and scrapping the province's cap-and-trade system, which puts a price on carbon and has added 4.3 cents a litre to the price of gasoline.

Currently, drivers pay 14.7 cents per litre of gasoline in provincial tax and 14.3 cents on diesel. The Tories would reduce both taxes to nine cents per litre, which they say would mean drivers pay $1.19 billion less per year.

But that also means that money isn't going to provincial coffers, along with $2 billion that the province brought in from cap-and-trade last year, and Ford was vague on how he would make up for that lost revenue.

Speaking in Ottawa, Wynne cast doubt Thursday on the impacts of Ford's pledge, given that global forces tend to be the largest factor in gas prices.

"I know he's saying that he'll take 10 cents out -- we know that most people won't feel that," she said. "The reality is that the prices fluctuate -- vastly, wildly."

Municipalities receive two cents per litre from the provincial gas tax, and that money is earmarked for transit funding. The Liberal government announced last year that they would increase it in 2019 to 2.5 cents a litre, and up to four cents by 2021 -- increases the Tories would maintain.

Horwath spoke about how an NDP government would fund half of the operating costs of municipal transit. She highlighted her Toronto-focused promises outside a subway station, saying she would also prioritize building a downtown relief line to relieve subway overcrowding.

She, too, took a swipe at Ford's promise.

"Mr. Ford again has not been clear with people about what the impacts of his announcements that he makes are," Horwath said. "And I look forward to the day when we can actually see a firm plan laid out by Mr. Ford. At this point, we haven't seen it and I think people deserve so much better than that."

Ford has not yet released a fully costed platform.