What do you mean reducing car volume? You asymptotically approach "bus" the more people you put in a vehicle. Turning one bus that holds ~50 people into 12 smaller buses that each hold 4 people doesn't solve anything as far as I can see.

Re: electric, this is a good step but we still produce most of our electricity (by far) by burning fossil fuels. Plus we lose energy in transmission/storage so it's a net loss.

Why are you ignoring all the traffic right now that isn't busses?

Let's say we currently have one bus and twenty cars.

If we replace that with 12 vans and 5 vans, respectively, that leaves us with 17 vans.

The road is now less congested and less polluting.

(There's no reason to expect all the current cars to be replaced, but there's no reason to expect all the busses to be replaced either.)

I guess I'm not super interested in the pretty small difference between van and bus. Grandparent's point was cars are better because they don't make a bunch of stops and they don't wait for people to get on/off. As you add people into vehicles you lose those advantages, but you lower your overhead.

But as more and more people work (global population is still increasing), this doesn't scale. Commuting is the problem, not humans having yet to find the perfect commuter to axle ratio.

This is my problem with self driving tech in general. So much energy and engineering has gone into solving a problem we don't need to solve. The answer is more light rail and more remote work. And if you think it's a tech solution to a political problem, I'd point you to all the political problems Uber is having. It's just, idk bad planning or something.