1) humans, including children, should be able to move through the public realm safely, no matter if they walk or bike
2) we do not want all the space in cities to be taken up by cars
Self-driving cars help with reaching goal number 1 partially, but it is not sufficient. Bike paths and other non-car infrastructure is also needed.
In terms of goal number 2, self-driving cars might open up a political chance to ban on-street parking.
You're right that they alone won't fix the problem, but I think they don't make it worse either. Traffic in cities is already limited by capacity, not by demand.
Changing the roads and infrastructure is the only way to avoid that fundamental physics problem.
But given how politically difficult it is to change--and especially to take away--existing infrastructure, and how much easier politically it is to introduce new tech, I hold out a smidgen of hope that driverless cars might help us inch in the right direction. Because they'll be managed by companies rather than individuals, they almost certainly will be required to adhere strictly to speed limits and other traffic laws, can be programmed to give bikers and pedestrians a wide berth, and won't (I hope dearly) get road rage. With luck and a sufficient volume of autonomous cars, this could help more people be comfortable riding with cars until we can get enough political will to build some decent infrastructure for non-car-users. And at this point I'll take what I can get to keep the ball rolling (and hopefully accelerating a bit) towards a friendlier future.
It could:
- reduce parking, so stuff can be more nearby
- reduced car ownership, waymo is not gonna let you buy a car from them
- walking 5 min to tram/metro might become interesting. Especially if there are no taxis available.
- cities can limit traffic, for example by reducing lanes and people might only notice by increased cost of taxi.
- people would not find out if you remove a couple of roads, they are checking their phones anyways.
Note that you could get rid of normal cars by increasing parking costs
Automating car traffic will lead to more car traffic. Today the number of cars on the road are limited to the number of drivers. If the drivers are removed, there can be even more cars, just driving around empty to go get someone. Even if demand for transit remains the same, driverless taxis have the potential to double the number of trips that need to be take. From going to a place and returning home (2 trips), to empty to pickup, go to a place, empty to pickup again, and returning home (4 trips). At scale, this will be a nightmare.
To reduce car traffic we need to build alternatives to cars (protected bike lanes, rails, etc). We will never get people away from cars by building more/better cars.