Seoul actually removed an urban freeway. Result? Less traffic congestion:
http://grist.org/infrastructure/2011-04-04-seoul-korea-tears...
Go figure.
That was funny considering I'm now living in LA. I was thinking, "You don't know traffic, buddy".
I do admit that the downtown core gets bottlenecked at certain times of the day. But it's better than traffic all the time at most hours of the day, like in LA.
The majority of people living in Southern California commute via freeway, and generally many people commute 70 mile roundtrips across town or from the valley into LA, and than for nightlife or a trip to a favorite bookstore etc, another ~70 mile round trip across town is totally normal.
Until there's more jobs available near affordable housing, millions of people in LA will continue relying on the freeways. The train is being slightly expanded into downtown Santa Monica, but that's not really a big improvement for LA - what would help the most is better transit lines between the San Fernando Valley and LA.
But when the time came, nothing happened. People adapted.
What actually happens is that the level of traffic basically stays static, and people travel using other means.
The level of automobile traffic moving through the downtown core is unchanged since the 1960s even though the population and amount of people working there has massively increased.