Absolutely avoid 4 way intersections use the brick stacking if you want to pack in with grid. 3 ways clear easier than four ways that seem to just clog. Avoid all the truck shipping use rail and ships to ship goods if you do mine,drill them. NO recycle ever.....just use garbage avoid recycling. Balance your workers with jobs and keep just enough shops to have 0 commuting in and out. Keep your schools full and just push your happiness with services and freght depots by your I. Balance and no 4 ways and management of the traffic you add in will help you reduce clogs.
Only way i use a bus depot is just a dual depot system i put one in middle of my highly populated residental then another depot in the middle of my work areas or by my college. And then you the have one destination and arent running round in circles doing little. This only reduces the car traffic about 25% and takes up a large area.