Traffic problems

To partly answer my own question (after a few days of experimentation), putting buildings in double strips (back-to-back) seems to be fine... so far.

I've learned that traffic in this game is designed to cause problems for no reason at all. For example, I'm "maxed out" at level 11 (max residency with 2 residential zones deliberately not built, 100% satisfaction, and able to maintain that for hours with no changes to the city while playing), but if I close the game for 8 hours to sleep, I log back in to find traffic congestion and falling approval ratings. Absolutely nothing changed, except an unexplained boost in traffic (from green to red overnight).

My conclusion: The game makes problems for the sake of making problems, even for controllable issues like traffic. Since it "cheats" it really doesn't matter which layout you choose.

the trick is to avoid intersections. Make one long continuous road and you will greatly reduce traffic. Also, to take full advantage of space, always have your building in rows of two or back to back. You only need one side to touch the road  so its a waste if you have everything single-file

When you do have a traffic issue, just moved the one abandoned building to another spot (not on the same road) and the traffic problem will go away. This will save you from having to upgrade your roads.