I take public transit and walk about a mile to work. I bike when I just need to go on a small errand. I drive a fair amount for other stuff.

Sidewalks work in cities where traffic (vehicle and pedestrian) is always high and areas where you have massive amounts of space for them (mostly places built up after WW2). For areas where sidewalks are not practical a wide shoulder is almost as good IMO. Obviously it depends on the nature of the road as well.