The first thing I was able to do as exercise after the doctor took my cast off was bike. Walking was still a too little too slow to be considered exercise. I did a few laps around the Central Park loop with very little effort - just went very slow, especially on the hills. But slowly biking was easily 3x faster than the average jogger. Unfortunately on the regular streets, cyclists feel compelled to go faster because of all the cars flying past them, cutting them off and honking at cyclists they get stuck behind.

Really like this!

There should be a lot of local design work focused on making bicycle-type technology more broadly accessible to young children, the elderly, and disabled. Most likely would require recumbent bicycles and tricyles and hybrid human-electric powering; i.e., bringing urban human-powered technology to a fine art. Seems like it's been done in Europe for some time now.

Ultimately, could provide much more convenient, comfortable, and practical transportation for everyone.