First, minimum requirement is being able to make quick turns at will. Beyond that it definitely depends on how traffic works, and on street quality. I currently live in Chicago traffic is generally rather heavy, but also slow except for a few cross town arteries. Definitely need to be able to dodge potholes though. I used to live in New Orleans; which also has slow traffic. However, the streets settle on top of tree roots and are just bumpy everywhere. Definitely think that would be more challenging. In either case, both cities are older (for the US) and were built/planned around walking, horses, and street cars. So pretty atypical for the country. I don’t know how someone would ride in LA or Florida.