The transportation structure of Japanese cities can be decomposed into pedestrian and vehicular networks. In some places they run side-by-side, in other places they overlap (woonerf), but for the most part, they are completely separate.

Both of these networks are hierarchical in form:

Hierarchy of Driving

1. Woonerfs – slow and very narrow streets where people and cars mix.

2. Narrow Streets – streets just wide enough for a pedestrian lane marked by painted lines.

3. Boulevard – streets with physically separated sidewalks.

4. Expressway – usually elevated or underground.

Hierarchy of Walking

1. Residential Laneway – very narrow, no shops … usually impassable to cars due to narrow width or the presence of steps.

2. Woonerfs – slow and very narrow streets where cars and people mix.

3. Narrow Streets – streets just wide enough for a vehicular lane marked by painted lines.

4. Boulevard – sidewalks with physically separated streets.

5A. Tunnels & underground shopping malls connected to train stations.

5B. Shopping streets and arcades (usually connected/adjacent to train stations).

5C. Nightlife Alleys – narrow alleys lined with bars, izakaya, etc (usually adjacent to train stations, e.g. Omoide Yokocho)

The two networks run side-by-side or overlap only in the case of Woonerfs, Narrow Streets, and Boulevards. These are the middle ranks of the pedestrian hierarchy, and marginal in two ways:

Over 1/3 of the total length of Japanese streets falls into the Residential Laneway category (too narrow for cars). The vast majority of shops and businesses are located at the other end of the pedestrian hierarchy; underground shopping malls, shopping arcades, and “nightlife alleys”.