'Jane Jacobs Goals Through Robert Moses Tactics': Community planners don't have all the answers.

• Author: Tuohey, Patrick

IN THE YEARS after World War II, flush with cash and optimism, American planners "skipped the messy iterations" of gradual urban and suburban growth, Charles L. Marohn Jr. explains. Instead, they subsidized ambitious new developments and saddled them with codes aimed at keeping them static. After all, once you've figured out the perfect design, why let anyone tinker with it?

"There is no anticipation of change, incremental or otherwise," Marohn writes of this approach in his book Strong Towns. "The building won't adapt, the block won't evolve, and the neighborhood won't transform over time, at least not easily. As it is built, evermore will it be, world without end."

The design wasn't really perfect, of course. These massive community plans made few accommodations for the human need to make adjustments based on experience.

Marohn, a professional engineer and land use planner, co-founded Strong Towns, a nonprofit dedicated to improving the development and growth of cities. His eponymous book at times may seem like a romanticized view of yesteryear, when city leaders were just... better. But city leaders weren't better before the rise of zoning and similar tools--there were just fewer of them, and they had less authority to carry out grand schemes.

Marohn takes readers everywhere from ancient cities to post-Civil War rail towns, demonstrating how urban centers once grew organically, constantly adjusting themselves to account for new information. Many of these places failed, but the ones that thrived evolved incrementally, taking on additional responsibilities for services like roads and public safety--but always doing so slowly.

MODERN PLANNERS HAVE failed repeatedly to accommodate the realities on the ground. In his 2018 book Order Without Design, Alain Bertaud recounted his work as an inspector in 1965 Algeria, where residential building permits insisted on "the rules, norms, and regulations for land development and construction" of France. French planners thought they had perfected urban design, so they saw no need to take into consideration the "income, culture, traditions, and climate" of this distant North African country.

Under such end-of-history planning, communities cannot adapt. You needn't go to Algeria to see examples. Consider the challenges a homeowner faces if he wants to have a "granny flat" on his property, or the gauntlets that must be run by such entrepreneurial innovations as Airbnb.

Many homeowners have bought in to that...