It is an axiom of traffic planners that increased speed due to capacity building is temporary; as traffic flows more smoothly, word gets out, and that attracts more traffic, eventually causing the same traffic-flow issues as before. The inevitable conclusion is that we cannot possibly build enough roads to satisfy demand, so we must consider alternative transportation systems.
This country has not had a comprehensive transportation strategy in decades, but now is an excellent time to consider one. And that means we need to take a hard look at what role highways should play and how they fit into the broader transportation network. Sprawling car-centric cities like Los Angeles, Phoenix, Salt Lake City, and Dallas are rushing to build new mass-transit systems—they have to; the roads they have cannot satisfy demand. So they must harmonize with other modes of transportation to reduce the stress on existing roadways as much as possible.
Remember- public transit makes life better for everyone. Nobody likes being stuck in traffic. Everyone wants a little more time in their day. Everyone wants cleaner air, better water, and stronger communities-- even people who love their cars. Along with Wired, I previously argued that recreational driving is not the problem, and that even auto addicts ought to be able to reap the benefits of a more diverse transportation system. It seems that the auto addicts agree with me.