Comment by jnicholasp

You may be partly right.

But self-driving cars will enable a sort of ad-hoc, on demand carpooling style 'mass' transit: something like ten-passenger vans that deliver commuters from similar downtown areas to similar home neighborhoods. If only ten percent of commuters switched to that method, taking ten cars off the road and replacing it with one van, the volume of traffic drops immediately to 91% of what it was. That alone, plus significantly smarter, denser, more efficient, networked AI driving, will hugely reduce gridlock.

And at some point as more jobs get automated, and the jobs that remain human-accessible become more knowledge-based and less presence- and specific time-based, we'll move away from the huge spikes in traffic at 8 a.m. and 5 p.m., spreading traffic volumes more evenly out across the day.