Why does THIS HAPPEN in Cities Skylines? (Gravelous 7)

In this series I will try to build a city using only gravel roads. I am not allowed to use traffic managing mods. I am allowed to use public transit, as long as they aren't allowing regular vehicles using them.
Have I cracked the code to perfect traffic flow? Will this fail miserably? Join me to this journey!
In this episode I expand the city, I create a new campus area and add a train. But the big question is, why aren't all of my buslines working?
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