This week's trophy for counter-intuitive statements goes to Gray's sentence:
"By combining these liberal land-use regulations with narrow streets shared by all users, we ironically find in many trailer parks a kind of traditional urban design more common in European and Japanese cities."
Time to hone the intuition, then.
RECLAIMING "REDNECK" URBANISM: WHAT URBAN PLANNERS CAN LEARN FROM TRAILER PARKS, by Nolan Gray (Market Urbanism via Strong Towns)
... Trailer parks are not only cheap due to manufacturing; they’re also cheap thanks to their surprising exemption from most conventional land-use controls. Most cities zone very little space for trailer parks—presumably a reflection of the general bias against low-income housing. But where they exist, they are often subject to uniquely liberal land-use regulation, with minimal setbacks, fewer parking requirements, and tiny minimum lot sizes. The result is that many trailer parks have relatively high population densities. The New World Economics blog explains:
If you had 70% home plots/15% roads/15% shared amenities like parks and squares, 1000sf plots, and 2.5 people per household, that works out to population density of 46,000 people per square mile — with one or two story construction! At this level of density, compared to about 9,000/mile for the denser Los Angeles suburb, you could easily have a lot of neat commercial stuff (bars, restaurants, shops, schools, etc.) within walking distance.
By combining these liberal land-use regulations with narrow streets shared by all users, we ironically find in many trailer parks a kind of traditional urban design more common in European and Japanese cities. With functional urban densities and traditional urban design, the only thing missing in most trailer parks is a natural mixture of commercial and industrial uses. Many urban trailer parks likely bypass this zoning-imposed challenge by locating within walking distance of commercial and industrial uses.