I just purchased Sim City today, I installed the whole thing smoothly but when I go to boot up the game it crashes. Try setting the Origin and Sim City desktop icons to Windows 7 compatibility mode.
I get the wonderful "Sim City has stopped working, windows is looking for a solution to your problem" message The screen goes black for a second (not the full screen just some in the middle) and the game cursor appears. Also, right click them and choose "Run as administrator".
There may be an instance of either still running in the background after the error so reboot your computer or end the processes in Task Manager before trying again.

The traffic issue was totally fixed in Update 7 and there is no longer traffic congestion and your sims will use mostly the mass transit.
You can have very high populated cities now with no traffic problems.
EDIT TO TEXT BELOW: A few days after update 7 there was a new secret patch that they did not list on the update list. So ignore the statement I made below because they brought in a new patch that made traffic come back.
There are many traffic related bugs listed so much that I don't want to delete them all.
I can recreate the issue by gifting a firetruck to a neighbor city. This happened twice in a row, when doing the same thing. So, maybe something hangs, due to a server side issue.
My game tends to hang (music still playing-force task manager) when I want to look at the bars on my education or crime tab.
Apple removed the Game Center stand-alone app with the i OS 10 update, but your games are still saved.
If you play on an i OS device, you probably connect your games to Game Center so you can save your game data and play on multiple devices.
Other times I can play for a few minutes but as soon as I go to the market, and select an item to buy, it crashes repeatedly. My husband's game on a regular i Pad never crashes, but he is on level 11.
I'm wondering if the complexities of the higher levels have anything to do with the crashing.
But switch back to that main city and bam, within 5 minutes, the game freezes.