>>1714792>>1714935It's true that living without a car in tokyo is completely possible, and depending on where you live and work a bike isn't even necessary, but the actual difficult to solve problem isn't passenger traffic, it's commercial and utility traffic. moving physical stuff around to each individual location that is required over distances both long and short is very difficult to accomplish efficiently without trucks.
Of course, OP's question was technically "without *cars*" so I guess if you think that truck traffic is totally fine then the answer to the question is "high density mixed zoning with an extensive subway network."
