I grew up in a very white city, very car-oriented city in the US and did use the city bus system over the years (during high school, and then later after I got hurt and couldn't ride my bike for a while). The basic problem with that system and others like it is that despite all the best intentions and efforts of the folks who ran the bus system, no matter what they did, even in the best case scenarios where the buses were on time and moving quickly, taking the bus sucked because going anywhere on it involved a long, unpleasant walk along a busy roadway on both ends of your journey. When a city is planned for a car, all the housing is detached single family homes, and all the businesses are surrounded by massive parking lots, everything ends up very far apart. Then add in the real world delays, traffic, and weather, and the bus becomes something that nobody wants to ride, and is only something used by people who have no other choice, so my city's buses tended to be full of homeless folks, people with mental health conditions, and the poorest of the poor. So maybe race tensions have something to do with it in some places, but if you're stuck with a built environment that's hostile to anyone not in a car, you could replace the buses with private, single-occupant limos, and if they had to use identical routes/stops the experience would still be awful overall.
