Klinkenberg reworks Calthorpe’s urban network

Peter Calthorpe’s “urban network” inspired architect Kevin Klinkenberg of Kansas City, Missouri, to offer an alternative system — clearly indebted to Calthorpe’s proposal, but with assumptions drawn from current retail methods, open space planning, and historical precedents, mainly in the Midwest. Klinkenberg, a principal with 180 Degrees Design Studio, distributed the plan to members of the Pro-Urb e-mail discussion list.

The most crucial change suggested by Klinkenberg is positioning of arterials a half-mile apart rather than a mile apart. Conventional planning errs in placing divided arterials one mile apart, with collector roads intermittently situated between them, Klinkenberg says. “The collectors are generally not consistent in either connections or design, and in many cases are simply not useful as major streets. Therefore, most of the traffic (even local) is pushed to the mile-spaced arterial streets.”

Calthorpe accepts the one-mile spacing, though with modifications, such as building “transit boulevards” at four-mile intervals instead of standard arterials. Klinkenberg studied three Kansas City area communities — the city’s Century section, J.C. Nichols’ Country Club District, and the postwar suburb of Prairie Village — and concluded that half-mile spacing of major streets works much better, producing “street sections that are conducive to good urbanism.”

Why is half-mile spacing superior? More frequent major streets provide greater choices in every direction, increasing “exponentially” the ability to handle traffic, Klinkenberg says. The finer-grained pattern encourages walking and biking, eliminating some auto trips. Transit becomes easier to reach. With movement more dispersed, intersections can be smaller. “Many roads are oversized simply to deal with intersection design problems,” he points out. “Roundabouts are very useful in this area, especially if they are single-lane,” he adds.

Klinkenberg suggests placing boulevards at two-mile intervals. Nearly all multiway boulevards in the US have functioned as residential and civic streets, he notes. Commercial uses have cropped up only intermittently, generally on side streets. Retail should be located elsewhere — in “tightly-scaled environments, where shoppers can see both sides of the street, and can easily cross over if they desire to,” he says. “This necessitates a very tight street section, ideally no larger than 2 travel lanes plus angled parking.”

“The Calthorpe proposal to combine major transit lines with boulevards works well, especially with a more frequent network of streets connecting to them,” he says.

Other elements of Klinkenberg’s proposal include:

• Construction of a parallel “avenue” (a substitute for a standard arterial) within two blocks of the boulevard, to accommodate commercial activity.

• Freeways spaced farther apart, preferably at intervals of 12 to 16 miles.

• Elimination of Calthorpe’s proposed truck-dominated throughways.

• Placement of large centers at the intersections of two boulevards, but on only one corner of the intersection. The other three corners would ideally have high-density residential, civic, and convenience uses. This is essentially the situation at Country Club Plaza.

• Placement of smaller centers at intersections of avenues, “where they can be appropriately-scaled and configured as ‘main streets.’ ”

• Use of parkways along important natural areas, tied into park systems.

• Placement of major industrial uses at “combined multi-modal facilities, for transfer with air and rail transportation. Secondary industry can be located at freeway interchanges, but should maintain some residential component,” to provide affordable housing.

Klinkenberg agrees with Calthorpe that “dealing with the arterial roadways is a critical problem of our time,” and he voices hope that his own proposal “can be a primer for a thorough investigation of the issues raised by Calthorpe and others.” Klinkenberg may be reached by e-mail at kklinkenberg@180deg.com.