Maxis has detailed some of the fixes being done to SimCity in terms of traffic routing and tuning, making the game more efficient in that regard.
For example, city servants on patrol like police cars and garbage trucks will be smarter in their duties. "The garbage trucks will be one area where you should see big improvements as they will claim every open spot along an entire side of one path where their current carrying capacity allows. So you may still see two garbage trucks picking up on the same street, but one should be on the right side and the other on the left," noted the blog.
The "Before" picture showed the green route for the garbage truck was longer than necessary. The "After" shows the green truck now knows the orange truck was already going to handle the house on the right and went to the house on the left instead.
The update will also deal with traffic congestion and routing for that as well. Clickto read the rest of the blog.