I don't know I think something has got to give before YIMBY can move forward. For example, communities where new residents are simply not allowed to have a car. I'm just shocked no one cares how much traffic will increase if you increase housing. It's already past capacity. Not sure why the fire-department can't put a max-capacity on a freeway when they can on a per-building level. If we restricted our freeways to have 10% of the traffic they do, maybe things would get better in cities.
This is backwards, traffic doesn't come from housing, traffic comes from jobs.
Rush hour is from people traveling to jobs, not from everyday living. So if you want less traffic, get rid of the jobs in the area, or provide ways for people to commute other than by car.
In fact, putting housing closer to jobs is probably the best thing that could be done to reduce traffic. At least then people have a chance to live close to where they work, and are on the road for fewer miles.
As it is, people live further out, travel further, and create more traffic than they would if there was more dense housing close to jobs.
People can't afford housing where the jobs are, because there isn't enough housing available there. So a large fraction of people end up moving far away and commuting in. That's how traffic happens. If you want to decrease traffic, build more housing where the jobs are.
A more direct example - if people have to live in McSprawlsBurg and commute an hour each way every day to work in NIMBYville highways and endless leagues of single family copy pasted houses will be built to accommodate job demand in that city, and you will get ludicrous amounts of traffic.
If NIMBYville stops being awful and recognizes how high the land values are they dezone the city limits to enable substantially higher density. And then, a decade later after the demand bubble has been drained, you might finally have the workers living in the actual city they work in, commuting by train, bike, tram, walking, etc instead of with cars that, unless you go out of your way to subsidize, will be prohibitively expensive to own when the square footage land value is so high.
And everyone wins in that world. If you previously owned an upzoned house developers will buy your house for more than they would if it were just zoned for a single family dwelling because they can put a dozen+ apartments on it. Letting density happen would mean you can actually choose between a small inner city condo or apartment that dosen't cost a magnitude more than a several thousand square foot house fifty miles away because when housing demand happens in the city housing can actually be built to meet it.
It is all wrapped up in short sighted greed on the part of everyone involved. Nothing gets better because nobody wants to wait for the best outcome if they can make marginal victories by sacrificing the well being of the whole and even their own long term prospects in the immediate term.
Traffic doesn't have to increase with higher density. That's what public transit is for, and cities like New York or Tokyo (especially Tokyo, which has very little traffic jams) manage to increase density without scaling traffic proportionally.
