> Cars are by far the least space-efficient method of transporting people

Not true in practice even if true in theory; in many places the average full-size bus contains fewer people than would fit in a minivan.

The problem is you need 5-10 years of reliable public transit in an area before non-transit users begin to convert (or transit users begin to move in).

If you myopically look at the instantaneous usage of infrastructure then you could argue that most roads are pointless because they are, on average, empty.

The bus might have less than 5 people on it at any given moment you observe, but over its >2 hour route it transports dozens or hundreds of people between stops.

Passenger-mile vs vehicle-mile is a useful metric (you can add driver-mile if you want, or cost-mile) but you can probably do something similar with some measurement of storage space, too.

A full minivan ranks surprisingly high on all of them, which is one of the reasons it's disappointing that carpooling and such aren't discussed as much anymore.

Or you can start with minivan buses, and switch to traditional one when minivans stopped being enough In my city less common routes are still purely minivan because why not. Some seasonal routes (more relevant in summer|winter) are also partially or full minivan.

(sidenote: I'm pretty sure it started because few guys with minivans noticed that some areas were under-connected by buses and just started a business driving those routes back-and-forth on a schedule. Then some regulations were slapped on top. So it looks like public transport have tendency to spontaneously appear in denser areas)

These used to be called jitney cabs or https://en.wikipedia.org/wiki/Share_taxi#Jitney (basically, cabs that travel like busses) and are still common in many parts of the world.

In Mexico it was always a decision of "do I walk a bit further to get the jitney and pay a bit more, but likely go faster (it stops picking up passengers when full and just goes until the first drop-off), or do I get on a bus sooner for cheaper but likely slower?"

Suburbs (with local amenities) with light rail connectivity into urban centres might actually be awesome.

I really wish someone would be a modern city from scratch.

Depends on the trip. I've timed many trips bike vs. car in my city. Bike is usually faster (or very similar time) because the average speed through a city is actually pretty slow. There's a lot of "hurry up and wait" with cars (rush to get to the next red light) and on my bike I'm frequently passing long lines of cars stopped at lights.

And parking is a time sink. There's a place in my city that has huge parking garages with lots of parking but you still have to drive through a few levels of the garage, park, and then walk back down a few flights of stairs, then walk to your destination. I just park my bike right outside of my destination with the wheel lock. Street parking is always awful in populated cities, and I never have to worry about it. I always park right at my destination, where ever it is.

In suburbia, cars are faster because the average distance per trip is a lot longer. But it's ironic that the reason why the average distance is longer is BECAUSE it was built for cars so everything gets spread out! Cars are a solution to a problem that they created.

Not the case as density increases: once roads reach their capacity, space inefficiency quickly becomes time inefficiency. That's why some cities have started introducing congestion pricing.