How's your mass transit?

I have not played the second part yet, only the first, however, I know that you should aim for living and shopping to be close by, best with some of the mixed used buildings. Then Industrie not too far away and downwind. Then set up public transport. A bus line that only serves living, or only runs in the industry sector is unhelpful if they never meet anywhere. People want to go from living to commercial and industry. Create alternatives to cars. Create foot paths and bike lane shortcuts.

Have an eye on the intersections, do you have traffic lights were a give way sign would be better? Do you follow the road hierarchy artery roads - collector/ distributor roads and then local roads? The higher up the fewer intersections you want on the road.

One important thing to remember is that sometimes more roads and bigger roads will make traffic slower.

If the only way into a neighborhood is a single high-capacity interchange, everyone uses that and everything is fine. But if there are lots of little side streets that could get into that neighborhood, suddenly you have hundreds of semis clogging up residential areas looking for a shortcut, so the residential traffic backs up behind that, which ends up blocking the big interchange we really wish the trucks would use instead, and now it's a huge mess.

Likewise, if you have a huge road with lots of little businesses on it (the dreaded "stroad") all those lanes make it hard for cars to actually get to where they want to go. So you have people who turn onto the road and suddenly need to cross four lanes to get to their destination, which slows down the cars just trying to get from A to B, so the whole road stops working. In that case, putting the commercial zones on a small side street with the big multi-lane road dedicated to long-distance travel with no zoning on it will work a lot better.

If you want to see some examples of really smart traffic handling and city design, check out City Planner Plays on YouTube. He builds really pretty cities that are also super functional.

"changing lanes at the last minute"

Can we please get a mod that nukes these people from orbit? Its literally worse than real life drivers.