Calles Sin Carros: Mexico City's Weekly Car Ban

"Every Sunday morning, some of the biggest streets of car-flooded Mexico City are handed over to bicyclists, who roll in by the tens of thousands. Joining them are skateboarders, rollerbladers, toddlers on push toys and parents behind strollers in what has become a weekly festival on wheels."

"The leftist government of Mayor Marcelo Ebrard launched the program last year, barring cars, trucks and buses from the regal Paseo de la Reforma and other streets around the historic downtown. Once a month, the route is expanded to form a 20-mile, engine-free circuit called the Cicloton."

"The cyclist's gain is the motorist's loss. But city officials seek to limit the traffic snarls by opening alternative routes and letting cars across key downtown junctions once the bikes have passed. On a couple of short stretches, cars and bikes share the street in rare harmony, separated by orange traffic cones. (If only the exhaust fumes stayed in their own lane.)"