FORTUNE -- Last week, Tyler Cowen, the economist and author who blogs at Marginal Revolution, posted an e-mail he had written to Hugo Lindgren, the recently departed editor of the New York Times Magazine, current acting editor of The Hollywood Reporter, about why he (Cowen) thinks Los Angeles is "the best city in the world."
Cowen likes the food, the drives, the soundtrack (The Beach Boys, The Byrds, Nilsson), the architecture, the art galleries, the concert life, and the fact that everyone goes to the movies. Also, he wrote, Los Angeles is the "best walking city in the U.S. (really), and year round."
A lot of people did not agree, at all. The main gripe can be summarized as, "Sure, the weather is good, but walking makes no practical sense here." As one commenter, Bathea, wrote below Cowen's post: "Pretty sure he means walking for pleasure, not walking to go from A to B." Cowen may have meant walking for pleasure, but it hardly matters. The collective wisdom is that put forth by Missing Persons: Namely, nobody walks in L.A.
This is not just wrong but dangerously wrong. Sure, L.A. is a great walking city for Cowen and other privileged folk, who almost certainly drive to a trailhead or beach or farmers' market before ditching the car for a stroll. In sheer numbers, Los Angeles has more bikers and walkers than Chicago, Washington, D.C., and San Francisco, according to a 2010 Benchmarking Report by the Alliance for Biking and Walking. These walkers and bikers aren't, primarily, Cowen and his ilk. They are people who don't have cars.
A few years ago, I spent a week traversing parts of Los Angeles by foot to write about transportation issues in the city. I also set out to put the lie to the notion that Los Angeles isn't a city of walkers; that, instead, the walkers are mostly hidden in the vastness of the place, somewhere (usually south and east) of where the wealthier residents live. The danger of the idea that nobody walks in L.A. is that this untruth has guided so much of the city's planning and transportation legislation, which has for decades lagged and ignored its bus and rail riders, who are primarily Latino and black.
The other lie about Los Angeles is the sprawl. Yes, the various lowlands which make up L.A. are literally sprawling, but the region is also the most densely populated urban area in the U.S. In his book Walkable City, author and urbanist Jeff Speck relates how urban density, as it relates to walkability, is not measured on a straight line but rather a sharp curve, "with most of the gains in efficiency occurring early on." That is, the difference between having 20 housing units per acre and 200 (the difference, say, between some of the most expensive L.A. zip codes and an average Brooklyn block) is minuscule compared with the difference between two units per acre and 20. "That means that," Speck concludes, "while Americans might have a long way to go to match European or Asian sustainability, a little effort can get us a lot closer."
During my L.A. walking week, I kept a strict no-cars rule and ended up forcing friends to walk with me if they wanted to go to a bar or restaurant that evening. Inevitably, the trek was shorter than they imagined, never taking longer than 25 minutes and always pleasant. In the evenings, the air would cool and smell faintly of eucalyptus and sagebrush. There were sidewalks. We nodded at neighbors. All it took was a little leap, and ignoring a big lie.