The Unexpected Consequence of Great Advances in Self-Driving Technology

Within a few years, self-driving cars will likely reach a point where "drivers" enjoy the same experience as train passengers — simply watching the landscape roll by while the car handles direction and speed.
I wonder if there's a catch.
We have family we love 200 miles north of us through thick traffic in LA and Orange counties. The stress of driving through those often congested areas is as big an obstacle to simply jumping in the car to visit them as is the time. But what about a world in which the stress isn't any greater than sitting at home in your living room? How many more trips will people suddenly be willing to make?
Yes, the cars will drive more efficiently — but there could be vastly more of them.
A prediction: the great advances in self-driving technology could create record congestion until we get to the next level of autonomous cars when they communicate and coordinate with each other in ways that enable them to drive faster and closer together than they ever could in situations in which traffic depends on human skill.