The government should step in to offer incentives to buy smaller cars.
It's not a terrible idea, but I don't think it would help traffic all that much. It might reduce traffic that is backed up for 10 blocks, to only 8 blocks.
One of the real roots of the problem is that massive amounts of people who are commuting from the outskirts into the city centre for work.
I'm fed up!
You live in the largest city in Canada. There is absolutely nothing you can do to change Toronto. If you can't handle big city life, then build a life somewhere else. Be happy you don't live in Chicago or London.
Or China

If they want us to help global warming bring back the Yaris, Fit, Mazda 2 and others.
That will not do a thing to "help global warming". Climate change is a natural phenomenon that we cannot control. Nothing the politicians are doing will have an effect beyond making peoples' lives more difficult, more expensive, and with limited choices.
Of course it would be a good thing to have relatively simple and inexpensive cars available that are not junk. However, it is none of the government's business what kind of vehicles people decide to drive. Low cost and ease of maintenance would be incentive enough.