YouTuber euverus modded Cities: Skylines to demonstrate how 30 different types of intersections have dramatically different amounts of traffic flow. A four-way intersection with no traffic lights gets a flow of 191 vehicles per minute, where a stack interchange can handle 1099 vehicles in the same time frame.
The big surprise for me was the roundabout, because we rarely have them in the Midwest or the West Coast. They seemed like a lot of extra space needed for an incremental benefit, but it appears they can be more efficient and safer, even weird ones.
• Traffic flow measured on 30 different 4-way junctions (YouTube / euverus)