The best solution to effect an immediate improvement to our transportation system is to encourage congestion. Much of North America's "congestion crisis" is comprised of discretionary traffic, which in turn is generated because of readily available and extensive road systems. For example, an estimated 40 percent of the car trips on U.S. interstate highways during peak hours are non-work related. Thus, by reducing the capacity capability of our road system, less "latent demand" is actualized in the form of new car trips as drivers are forced to reconsider their travel habits.
The Greater Vancouver Regional District recently adopted this philosophy in its Long-Range Transportation Plan, which states: "Selectively accepting congestion to change travel patterns is another (transport service) policy lever... Congestion is usually considered an evil; however, allowing congestion to deteriorate for the single-occupant vehicles is a practical method of promoting transit and carpools."
I suspect that this article's description of this in terms of "supply and demand" is the sort of thing that will make actual economists cringe, but I do think there's a sensible point hiding in there.
I've long thought that the absolute best thing that could happen for ease of transportation in San Francisco would be the bulldozing of every parking lot in the city. Public transportation in this town won't improve until people demand it, and people won't demand it so long as it's still relatively easy to get around town in a car. Cities can grow up or out. Tall buildings, or sprawl. I know which direction I'd rather see it go.