Walkable strees are fun. You don't have to repeat never ending drive-park-shop-drive-park-shop.... cycle. You are free to take time and stroll around, check this shop, buy a little snack from that place, as you feel like to.
photo by nodoca
If a town as a whole is designed walkable, you can have a glass of beer or a keg in a pub, and then walk home without worrying about DUI at all! Obviously, if the town is population dense enough, you will have a decent public transportation system that won't discriminate you even if you enjoyed a little bit of booze.
Narrower, walkable streets have safety advantage too. I learnt in my environmental planning class that the widths of the street affect how fast people drive. If the streets are wider, people tend to drive faster which increases the risk of accident.
Making the streets narrower and walkable (or making a town a bit smaller) would have many advantages; save land use, increase traffic safety, reduce your carbon footprint a lot ---- and it's fun!
This photo is Netherland that is as population dense as Japan. When population density is high and the land is scarce/expensive, people develop small but highly pedestrian-friendly, toy-box like neighbourhood that is fun to explore. Netherland has nice little lovely streets, beautifully decorated, narrow/tall apartments standing next to each other with no space in-between (which buidling was built first???) and a lot of pubs in walking distance!
photo by atsjebosma