The next thing is a driverless car and a driverless bus “docking” at speed, so you can change vehicle without affecting your trip time.
Economics will outcompete 50 self-driving cars going in the same direction for 30min when you could have one driverless-bus doing the same.
If this transition is smooth and fast, think what this will do to traveling time, car prices and property prices. How far can you travel without stops and no traffic jam?
In-transit transfers is a fascinating idea, but there probably more practical solutions to the problem you're trying to solve.
More realistic I think is finding the right size for vehicles somewhere in between the size of a car and a bus: A bus gets you somewhere at maximum efficiency while sacrificing accuracy (walking to and from bus stops) while a taxi gets you somewhere at maximum accuracy while sacrificing efficiency (roads full of single-passenger vehicles). Something like 6-10-passenger vans are probably the right middle ground to maximize both efficiency and accuracy.
Yep, and beyond that, there's still a need to remove cars from the world, both to fight climate change and to make cities livable again (see any video from the "Not Just Bikes" YouTube channel for support for this argument). Moving everything to autonomous cars (even, yes, electric autonomous cars) will not solve those issues. Smart urban planning and structural reform are the only things that really stand a chance there.
With the urban sprawl in the US you frequently will need to at least change vehicle once and that will likely involve a substantial wait and might involve a walk at least on one end. This quickly can turn what could take 15-20 minutes into a hour or more. A docking model as the parent suggest might address this.
I'm also gonna go out there and say what many are afraid to talk about openly. When I used to commute by public transit in SF the crowd frequently wasn't pleasant as a whole. There were a lot of very nice people going to work, but there also were a lot of folks who caused problems for others. People with mental illnesses, people who seemed to not have access to showers and folks who were just generally quite roudy. There were days were I wished that there was a separate compartment that's exactly identical but costs $0.5 more. I feel guilty that I wanted that, but I think that's just the reality of life in a country with such a unequal society. I think this is one of the reasons why public transit works better in countries with more wealth redistribution and a stronger social system.
I live in a city in Europe with excellent public transit (not stigmatized, clean, used by everyone from the pauper to the millionaires, for some routes faster and more convenient than a car). Sometimes it still sucks due to the waiting and the "last mile" problem. A 10-15 min walk from the nearest transit stop to the actual destination, having to change, the waiting times and lack of flexibility (the bus may only be going once every 30 minutes) means I'm still taking an Uber for some trips.
Smaller vehicles going more frequently with fewer stops and more routes would make public transit a lot nicer.
Economics will outcompete 50 self-driving cars going in the same direction for 30min when you could have one driverless-bus doing the same.
If this transition is smooth and fast, think what this will do to traveling time, car prices and property prices. How far can you travel without stops and no traffic jam?