I know! We build more roads and then there will be room for all the cars and the problem will be solved. This is the most rational solution to the problem.
Building more roads will work. Induced traffic is an evil lie peddled by socialist hippies who hate freedom.
Well I didn't say that this was about a "typical western nation" and even if we are strictly talking about the West for some reason this would still be a good policy in large parts of Western Europe which already have good mass transit and aren't as reliant on cars.
Also, I never said that this would be a change that would take place in a vacuum, so I don't see why you're assuming that it should. My original post refers to "easy policies", plural.
Lastly, I don't think you're accounting for the increased draw of public transport if people could be more confident that they could sit down on a bus or a train for their commutes, or at least not be packed in like canned fish.