Amsterdam wasn't built around cars, that's the key. Especially an oversized American road converted to big tree-dotted lanes wouldn't be particularly useful for

Amsterdam wasn't built around cars, that's the key. Especially an oversized American road converted to big tree-dotted lanes wouldn't be particularly useful for people if everything is still so far apart, like Dearborn, MI. Also, if you start with a small central area in an already dense city, you will find a lot more political support from residents and business-owners because there's a clear and immediate benefit to them. Rather than telling an entire city you're "fixing" their way of life and it'll take a long time to pay off.