There are common use cases for which cars remain a superior alternative.
Shopping is the main one. Cars allow shops to be very large (providing more variety and creating economies of scale), and the ability to site shops in cheaper locations contributes to lower purchase prices.
The other classic problem with public transport is that it cannot replace the point-to-point nature of cars. Sometimes that matters, sometimes it doesn't. But it matters for enough people that cars are the dominant mode of transport.
Self-driving cars will help some of this, particularly the car daycare problem. Though they will have problems of their own. Ever tried to get a taxi at rush hour? Ever been on a bus with suspiciously damp seats? People will still want their own cars and will still want to travel at the same times.
As an aside, one thing I really like about my city (Perth) is that there are a number of free bus routes in the CBD. You really do find CEOs riding the bus to get around.
Where I live shops are within walking distance, and since we have a kid we switched to having lots of food delivered once a week fresh from the countryside.
I am especially bullish on that delivery service. Sure, they use a car, but one small truck making the rounds seems a lot more efficient than lots of small cars driving to the store.
Shopping is a very trite activity, owning a car doesn't make it much better. In fact driving out to some shopping center seems to make shopping a day trip, which is one wasted day. I prefer to just pick up a few things on may way home from the tube, and ordering more complicated stuff from Amazon (plus the weekly food deliveries).
I don't think that "cars allows shops to be very large" really holds. Ever lived in Tokyo, Seoul, Singapore? They all have large stores and large malls and far far fewer cars per person.
What they do have is lots is support for shopping and public transport including wrapping packages so they are easier to carry (buying a printer they wrap a secure handle around the package to make it easy to carry home) and most stores offer relatively cheap and convenient delivery.
You can have minibuses where you can get on/off anywhere along the designated route. Farm these out to private operators (regulated, of course), and you will have lots of cheap point to point public transport. It requires a city to be dense, though. http://en.wikipedia.org/wiki/Public_light_bus#Pros_and_cons_...
Cars provide a circuit model. You go from point to point over a single dedicated "channel".
Any kind and combination of public transport does not do that. It is a packet model and you, the human, are the packet. You must change modes of transport and hope that they sync up, aren't running early or late, fit your schedule and so on.
Except in the cases where point-to-point travel takes substantially longer (very dense urban cores), I think most people will always prefer cars.
(Yes, I know the analogy is imperfect because the car can be seen as a packet blah blah blah. But cars are not sentient. Humans are and it is humans who decide what mode of transport to use.)
But, as opposed to real computer networks, packet transportation is much more energy efficient. Sending twenty people to the same destination in one `packet' uses much less fuel than having those people travel in twenty separated `circuits'.
As a society we seem to have mostly established the abstraction that energy is free and unlimited. From the recent explosion of amount of things humanity does we can see clearly how practically free energy is a desired state. However, we're not there yet. Until we really get there, forgetting that this is only a leaky abstraction is dangerous, as the leaks have deadly consequences.
I realise that on certain metrics public transport is better.
None of that matters. Who decides which transport to use? Humans. What measurement do they use? It's clearly not litres of diesel per passenger-kilometre.
"Humanity" is pretty good at economising scarce resources. But people are pretty clearly prepared to pay enormous costs (fuel, parking space, commute time) to have a private car. Arguing with revealed preferences doesn't change them.
Except that most of those costs (and lets include pollution) are externalities borne by other people, not by the actual car drivers. If people would have to pay the real cost for cars, things might look different.
If the city is dense enough, there will be minibuses crossing many point to points routes and you'll more likely to be able to travel point to point without changing mode of transport. Of course, it isn't guaranteed.
I personally think self driving cars can replace today's cars as well as public transport. Personally, I think it would be best if it were simply a government service like the post office where you go online and put in your driving schedule. Then their system will know every car on every road and can plan out the most efficient use of the cars.
The solution to this would be easy. Have a few narrow roads on which only special cars can transit (such as emergency vehicles), and permit a few (public?) taxis to circulate. The price to take one of these should be many times more what we pay today. So you want to do shopping? Fine, you should be able to afford the taxi.
Shopping is the main one. Cars allow shops to be very large (providing more variety and creating economies of scale), and the ability to site shops in cheaper locations contributes to lower purchase prices.
The other classic problem with public transport is that it cannot replace the point-to-point nature of cars. Sometimes that matters, sometimes it doesn't. But it matters for enough people that cars are the dominant mode of transport.
Self-driving cars will help some of this, particularly the car daycare problem. Though they will have problems of their own. Ever tried to get a taxi at rush hour? Ever been on a bus with suspiciously damp seats? People will still want their own cars and will still want to travel at the same times.
As an aside, one thing I really like about my city (Perth) is that there are a number of free bus routes in the CBD. You really do find CEOs riding the bus to get around.