I live on Sunnyside Avenue in Arlington, Massachusetts. The neighborhood was built as two subdivisions in 1948, with 42 duplexes (84 homes total). These were starter homes with 792 square feet of finished space plus a basement with a garage. I affectionately refer to them as excellent specimens of mid-century slap-up. They were constructed in the mid 20th century, and the builder just kind of slapped them up.
According to Richard Rothstein in his 2017 book, Color of Law: A Forgotten History of How Our Government Segregated America, “we have created a caste system in this country, with African-Americans kept exploited and geographically separate by racially explicit government policies,” he writes. “Although most of these policies are now off the books, they have never been remedied and their effects endure.” Zoning was one of the policies that contributed significantly to this outcome.