>But decreasing congestion? We already know how to do that,
Anything, automation included, that allows things to flow more smoothly will decrease congestion for a specific number of vehicles on the road allowing roads/intersections/etc to flow closer to their ideal capacity. (This principal holds whether you're talking about cars or buses, train networks, industrial facilities, etc.)
For example, if self driving solves some decent fraction of the morons who can't seem to merge in the size space that the engineers specifically allocated because it was sufficient for that purpose or can't turn left even through sufficiently sparse cross traffic you've just alleviated a lot of congestion.
In practice transit networks are bounded by the daily peaks so you'll never not have traffic jams and packed subway cars at rush hour but efficiency improvements mean these conditions will exist for a smaller slice of the day.
Anything, automation included, that allows things to flow more smoothly will decrease congestion for a specific number of vehicles on the road allowing roads/intersections/etc to flow closer to their ideal capacity. (This principal holds whether you're talking about cars or buses, train networks, industrial facilities, etc.)
For example, if self driving solves some decent fraction of the morons who can't seem to merge in the size space that the engineers specifically allocated because it was sufficient for that purpose or can't turn left even through sufficiently sparse cross traffic you've just alleviated a lot of congestion.
In practice transit networks are bounded by the daily peaks so you'll never not have traffic jams and packed subway cars at rush hour but efficiency improvements mean these conditions will exist for a smaller slice of the day.