Behold the common skateboard, a machine that can give new life to parks, especially those areas that previously seemed unusable. Little more than a plank of wooden laminate, this machine is shaped like a surfboard. Once brightly colored, it has been scuffed by hard use almost beyond recognition. On its bottom surface are two pair of wheels, fore and aft, that torque and bend and snap back into position.

On the top surface is a youth of 12 or 13 summers, maybe wearing a helmet or maybe not, but likely wearing some form of elbow and knee protection (even kids learn from experience, sometimes) who can make a weird music out of the sound of the wheels leaping off the edge of a ramp (KLIK-likk!!) or the sound of those same wheels landing on concrete (Kip-PLOKK!!) or a surf-like maneuver where the wheels sidle up the edge of an incline and make a hair-pin turn like a surfer. (GAHZZZ-zook!!).

Nobody needs reminding that the skateboard is ubiquitous - it remains the fastest growing sport in America - and skate parks are no longer novelties in public places. By now, dozens of California cities have built skate parks, even in cases where residents originally protested.

What makes skate parks really interesting, from a planning point of view, is the opportunity that skateboarding offers to remake awkward spaces--excess parking, languishing shuffle board courts, the dead zones behind baseball batting fences, detention basins, and all the other oddball spaces in parks that otherwise go empty. In many cases, after the construction of a stake park, these oddball spaces become the most popular and heavily trafficked part of the park. And despite the fears of youth-o-phobes, very little bad behavior goes on in these places, because the kids and young adults who come here regularly are dedicated athletes as fixated on their sport as surfers or downhill skiers.

The most interesting aspect of skate parks, from a landscape-design perspective, is their flexibility. There is no standard model, and indeed no two are alike, according to Steve Rose, principal of Purkiss-Rose RSL, a landscape architectural firm based in Fullerton. (With more than 200 built skate parks to their credit, Purkiss-Rose is the acknowledged heavyweight in this field.) Geometrically, skate parks can be long and skinny, or square, or round. The nature of each park is determined somewhat democratically, with local skaters, each of whom have their own preferences, consulting. In some cases, the skate park replicates certain features, like walls or stairs, that boarders enjoy using in their respective neighborhoods. Of course, there are always skaters who complain that courses are not challenging enough.

Skate park design follows two different approaches for two different styles of skating. The first, known as “old school,” is about bowls and long glides and the sensation of flowing movement, inspired by surfing. (Skateboarding originated with surfers, according to legend.) Rose also likes to incorporate curved walls reminiscent of empty swimming pools, one of favored venues of pioneering boarders during the early, outlaw phase of the sport; most skate parks, in fact, resemble empty, concrete-lined basins.

The second style, called “street,” consists of sheer drop-offs, railings and jump off points, inspired by the high-risk, high-impact style of boarding invented by enthusiasts who perfected their skills in the urban hardscape. In many cases, Rose said he combines elements of both old school and street, such as a smooth, flowing course of bowls and wave-like forms arranged around a group of tough-looking escarpments and ramps for the air-grabbers and grinders.

Space for spectators is important, but the seating must look improvised; bleachers are verboten. Observers are often budding athletes or admirers who do not think of themselves as outsiders. They want ring-side seats that let them feel the action. Often, a simple ledge around the skate park is enough.

The flexibility of skate parks means that these facilities can be installed just about anywhere. “Start with an under-used area,” said Rose.

He cited some examples from his portfolio. In Pomona (Los Angeles County), a neglected area for shuffle board and horse shoes became the basis for a skate park. In Santa Barbara, Rose used some parking spaces, replacing the lost spaces by re-striping the surviving parking area. A steeply sloped area in a park in Moreno Valley that was previously identified as “non-programmable” is now a skateboard venue. In Monrovia (Los Angeles County), adaptive reuse came into play. Starting with an unused armory building and a parking lot, Rose re-purposed the armory as a youth center, while replacing the parking lot with a skate park.

The approval process can be tricky. “City officials, especially plan checkers, have to be re-educated,” Rose advised.

First, neighbors must be convinced that skaters are not loitering hooligans. As for concerns about noise, Rose says skateboarding is no more noisy than street traffic (about 70 decibels). City officials must be convinced that liability for injury is no greater than any other sport played in parks. (The injury rate in skateboarding is surprisingly low, in contrast to the recent craze for scooters that engulfed emergency rooms with abrasions and knee injuries.) Building and safety departments have to be talked down from imposing ADA access requirements, which Rose contends do not apply for these projects, just as those rules do not apply for tennis courts or swimming pools.

The cost of building skate parks, in fact, is roughly akin to that of swimming pools, or about $40 per square foot. The facilities are finished in smooth concrete, and require minimal maintenance.

Best of all, skate parks get those insane kids off the streets, so middle-aged men walking home from Trader Joe's are not thrown off balance, falling into the bushes and spilling their paper bags full of Two-Buck Chuck and brie. My advice is to build the darn things so that you can start worrying about the rising popularity of the next urban-outlaw sport: scaling the facades of tall buildings with rock-climbing gear. Talk about an urban design challenge.