But that's the thing about induced demand. Of course widening a road temporarily improves traffic. But only temporary. That temporary improved leads to more people deciding to drive a car when they didn't in the past or even having different moving options in mind now which they didn't because if traffic. In the end traffic ends up the same if not worse than before.
That's not something the Internet came up with. It's been studied and researched for years.
It works on the simple principle of: If you make something more convenient to use, more people will use it.
Cars just don't scale. They can't do mass transport and aren't meant for that.
You need to make a city walkable and have a proper public transport system otherwise you will only ever lose even more money on car infrastructure while continuing to worsen traffic, heating up the city because of the sealed surfaces, making the city less desirable to actually exist in and worsening it's economy.
Build the city properly and people will actually choose a different option. No matter the climate in that city. Especially because heat is only worse with massive amounts of car infrastructure because they usually result in less green spaces and trees which provide shade and a cooling effect in the city.