It's not. I live a mile away from the busiest highway in texas. I've watched how city/urban area people drive. It's all about jamming shit up and then thinking they'll get where they want to go faster. Getting ahead of everyone else. Trying to drive smartly on these roads only increases the idiocy among everyone else. I've hung back behind a car with at least a car length between me and the car ahead of me, only to have the bitch behind me stand on the horn and gas as she swung her car on to the shoulder to pass me, all so that she could tailgate the car I was giving decent space to. Another example is me on my motorcycle, giving the driver ahead of me a car length between us, just to have the moron behind me run me and my bike on to the shoulder so he could tailgate the car in front of us.
Most people are inconsiderate morons on the road and no amount of lane expansions, extra exits, extra on ramps, or road/traffic signs is going to reduce the jamming that those fucktards are causing.