In Osaka / Tokyo / other large Japanese cities people ride bikes on the footpath instead of the road. They also ride comparatively slowly and the terrain is lar

In Osaka / Tokyo / other large Japanese cities people ride bikes on the footpath instead of the road. They also ride comparatively slowly and the terrain is largely flat so in the cooler months sweating is a non-issue. Additionally folding bicycles are very popular because, as you say, the apartments are often very small. Finally, because the cities are so compact you rarely have to travel a large distance to get to where you're going. So all and all, I agree with you, it's common in these places because the combination of these things makes riding very practical and they're noteworthy because of it. -edit- I forgot to mention that most apartment buildings will have stacked locking bike racks. This combined with the generally low rate of theft, easily available recycled (read: cheap) bicycles makes them very affordable and low risk.