Good density and not-so-good density

After seeing another blog post about how density is bad because Los Angeles is dense, it occurred to me to suggest that just as there is good and bad cholesterol, there is good and not-so-good density.

From a new urbanist perspective, good density is density that contributes to walkability: density near public transit, density within walking distance of shops and jobs in a place where walking is possible.

Density in the middle of automobile-dependent sprawl can be more problematic.  For example, Los Angeles may be dense overall, but its density is spread out evenly over the region (thus reducing the city's ability to have a strong transit-oriented core) and antiquated street design or single-use zoning may make some dense areas less walkable than they could be. 

This "bad" density is not always absolutely bad, since sometimes it is a stepping stone on the way to good density.  For example, a dense apartment complex surrounded by nothing but other housing and high-speed roads is not particularly walkable, but can be retrofitted over time if the road network is made more walkable or if commerce is added.

It seems to me that if a place has a high level of transit use (or, in a smaller city, walking to work) it probably has a lot of good density.  On the other hand, if a place has high density but lower levels of transit use than one might expect for that level of density (e.g. Los Angeles, Miami) it has more not-so-good density.