This mod greatly increases traffic density in major urban areas across the map; traffic elsewhere is kept to vanilla levels, which I think is realistic enough.
While this mod is closer to a traffic mod than a map mod, busy areas with increased traffic spawns have to be defined manually in the map editor, requiring map edits, simply modifying definition files to increase traffic spawn rates and limits like a lot of "realistic traffic" mods do would make the whole map busy with traffic, from major cities to unpopulated rural areas, that's why editing the map itself is necessary for decently realistic traffic density.
This mod also widens freeways and urbanizes some areas of Phoenix, just a small touch-up I've done years ago as that area has always bothered me in terms of accuracy. Use the available "Lite" version if you want only the scenery changes in the Phoenix Area and no edits to traffic density in cities.
As this mod has modified sectors in major urban areas throughout the whole map, all map DLC is probably required.

Credits: Quaristice