The way SimCity handled traffic was one of the major problems behind the launch of the game, with cars pretty much unable to work their way past a jam and just ignoring alternative routes in favor of the most direct one.
Maxis has addressed the problem by releasing patch 1.7 that, at least on my screen, eased the load of the streets quite visibly, making cities a lot more efficient, since goods need to actually be transported by trucks, and having them stuck en route isn’t exactly the best way to get the Simoleons flowing.
It has to be noted that the patch doesn’t get rid of traffic jams completely. Bad road planning with excessive intersections and misplaced bus stops can still create kinks in the lifeblood of your city, but it’s a very large step in the right direction.
Traffic isn’t the only problem addressed by the patch, as now you can also bulldoze the small and completely useless filler tiles built by the game between zoned areas. Considering how annoying they were, I say good riddance. Time for some cleanup.