Hi, while you're waiting for responses here, you may be interested in a few previous answers
/u/breakthegate explains the practice in What led Detroit to the state it is in today?
/u/lukeweiss discusses some ramifications in Why were the Late 70's/Early 80's a low point for many American cities?
/u/ked_man provides the example of Louisville KY in How did redlining in the United States create the racial make up of the suburbs?
These posts have all been archived by now, so if you have follow-up questions for these users, just ask here & tag their username to notify them