It's not SF specific, but nationally violence peaked in the early '90s in America: https://www.statista.com/graphic/1/191219/reported-violent-crime-rate-in-the-

It's not SF specific, but nationally violence peaked in the early '90s in America: https://www.statista.com/graphic/1/191219/reported-violent-crime-rate-in-the-usa-since-1990.jpg https://www.statista.com/graphic/1/191219/reported-violent-c... IIRC it was at least partly getting lead out of gasoline in the '70s: https://www.brookings.edu/blog/up-front/2017/06/01/new-evidence-that-lead-exposure-increases-crime/ https://www.brookings.edu/blog/up-front/2017/06/01/new-evide...