We may have a fighting chance if we ever get economic short range vtol air travel. Instead of a 20-50% increase in capacity like adding lanes (and probably driverless vehicles would be in this range as well) or a 5-10x increase (like building a highway), that might get us a 1000x increase in capacity. That might be big enough to move the equilibrium somewhere interesting.
This is braess paradox, right ? the reason for it is non-optimal selection of routes by users, because of lack of information. But Google maps doesn't suspossed to have that problem because it has more(real time, per road) information.
Problem with that idea is if you change jobs, you need to buy a new house. And moving that often can get lame.
Rain/snow: wear a coat, optionally overtrousers.
Hot: go slower if you normally race in, and it doesn't get much above 20 degrees anyway.
The population is too high and the amount of space too limited to make this a reality, at least in countries with a decent sized population.
Assuming drivers licenses are no longer needed, the amount of people that can drive will dramatically increase, which could result in a huge spike in the amount of cars on the road.
Any gains achieved by smoother traffic flow is likely to be dominated by this fact.
Maybe it would double. But a self-driving van could easily(between many passengers/more efficient driving) could increase traffic capacity by 10x,
Also, people don't feel safe driving at 60mph in a densely packed road, so they don't. This should be no problem for a computer, so you could have a densely packed highway but traffic still moving at very high speeds. Basically, flow velocity could remain constant as the highway becomes more congested.
Another optimization that comes to mind is that on city streets, your car would route around traffic light timing.