I don’t really like including pedestrians in there. Like sure, you can fit a bunch of people in a small area, but another point you shouldn’t ignore is the throughput over time, and pedestrians are by their nature rather slow. Obviously if you’re looking at shopping in a street lined by shops left and right, then that street becomes tailor-made for pedestrian traffic (and nothing else except perhaps bicycles). But public transport is much better suited for travelling any further distances, and that should be the main focus when deciding to ditch cars.
Sure! Both speed and distance matters a lot for throughput. The advantage of pedestrian traffic is that designing for it reduces the distance people have to travel and that it combines very well in conjunction with public transport, unlike cars. Also, the speed of mixed traffic is inverse correlated to the number of vehicles, hence is a special case in this regard where throughput may decrease as the volume per lane increases. The overall point however is that a single train can substitute a staggering amount of private vehicles (and who doesn’t love leaning back, listening to music and reading the news while commuting?).
