One of the reasons that taxis are licensed is that they're supposed to pick up everyone and anyone. Uber and Lyft don't seem to have that problem with race (AFAIK) but there are two other situations where people have trouble:

(1) small children, where you need a car seat (or two)

(2) people with disabilities - service animal, wheelchair, etc.

Analyzing the data would hopefully show whether people had to wait for 2 hours.

Also, as a substitute for race, it might be possible to see if certain areas are under-served or not served at all. Perhaps drivers are avoiding picking up in Harlem.