There's significant trouble with routing, delays, and reliability: A self driving car does nothing naturally different that a cheaper Taxi, and you can see the lack of popularity of the carpooling offerings Lyft and Uber had.
Ultimately the argument against lower congestion is even easier. Self driving cars for individuals make traveling less annoying than driving. So what we get is more tolerance for long commutes, and ultimately more miles traveled, with ups congestion. Now Timmy can go to his activities by himself, so mom goes elsewhere. Again, when we make something cheaper, we increase demand.
Uber Pool in SF was awesome when it was truly 50% of the cost. But they started hiking up the price (because they could) until it was maybe ~20% less than the full ride. And then COVID happened.
> Self driving cars for individuals make traveling less annoying than driving. So what we get is more tolerance for long commutes, and ultimately more miles traveled, with ups congestion.
That's fine. I did some modeling for that :)
Most of the optional commutes happen outside the rush hour, and the US roads have more than enough capacity for that. The true problem is the congestion due to low occupancy during the rush hour.
And if we want to speculate a bit more, self-driving cars offer an option of more flexible mass transit for truly bottlenecked cities. They can the make transfer from a larger bus into 2-seater local vehicles completely seamless. This is a more distant possibility, as it will require new infrastructure.
Ultimately the argument against lower congestion is even easier. Self driving cars for individuals make traveling less annoying than driving. So what we get is more tolerance for long commutes, and ultimately more miles traveled, with ups congestion. Now Timmy can go to his activities by himself, so mom goes elsewhere. Again, when we make something cheaper, we increase demand.