Mayor Enrique Peñalosa might have been forgiven for feeling nervous recently, when millions of residents took to this city’s streets on roller blades, bikes and horses in an officially declared Car-Free Day.

What if Bogotanos, rather than displaying the hoped-for civic mindedness, flew into a collective road rage over being ordered out of their automobiles?

But after a torrential downpour late in the day, the mayor had little cause for concern. For the most part, the unprecedented, Feb. 24 event went off without a hitch—and Bogotanos enjoyed the experience.

In an effort to break citizens’ addiction to their cars, some 800,000 private vehicles in this city of 7 million were banned, though municipal authorities allowed the free circulation of taxis, buses and emergency vehicles.

With so many cars sidelined, the city’s thick smog lifted and Latin America’s fourth-most-polluted city emerged into the sharp, clean light of the Andes.

For the first time in years, not a single traffic fatality was reported. Police dealt instead with unruly horses and fender-bender bicycle accidents.