Planning for Walkability? Concentrate on Commercial Density

"[W]alkability is usually measured not by how many people reside near you, but by how many services and shops you can access from where you live," according to a post on the blog Urban Khoze. "So to achieve great walkability, it seems that commercial density is very important." Metrics like Walk Score exemplify this claim, but this post takes a look under the hood, so to speak, by examining a model for proof that commercial density is even more important than residential density in achieving the goals of walkability.

The post begins by examining the example set by old American cities, where commercial buildings cover the entire lot and floor-to-area ratio of 150 percent to 250 percent. That density, however, often times clashes with residential densities just a few blocks away, with FAR in the realm of 25 percent to 30 percent. The lesson from these types of arrangements: "So old American cities had very high commercial densities on main street but relatively low densities in residential areas. And we know these small towns were walkable because they were built in an era where cars were still relatively rare, if not even before, when they didn't exist."

Following some of the implications of that example, the post goes on to set up a model with four scenarios of commercial and residential arrangement to reveal more insight into the importance of density in their relationship. The post's exploration of each of these scenarios informs many concepts that are helpful in understanding planning to improve walkability. The conclusion: "achieving commercial density is far more important to re-establishing walkable cities than densifying residential areas."