There are places where you would expect a bike share to take off—flat and relatively compact cities like Washington, DC and Montreal, places with somewhat sane traffic patterns and streets you wouldn’t be too terrified to bike in. Mexico City is not such a place. Traffic is often snarled, and the air is not just polluted, but perilously thin. The Mexican capitol is about 3,900 feet above sea level, and while the city has done a remarkable job in taking care of its notorious air pollution problem, it’s still pretty harsh on American lungs. Vast distances, nightmarish traffic, an oxygen to carbon ratio that makes breathing a sometimes-unpleasant experience—Mexico City is not a place you would expect a bike share to be wildly successful.

And yet, Good Magazine reports:

ECOBICI was first installed in six central city neighborhoods that flank Reforma and Insurgentes, Mexico City’s two grandest avenues. Travel along these avenues accounts for 40 percent of the city’s daily work trips. ECOBICI makes it easier to get to and from work, as well as to the Metro and Metrobús stations along the corridors.

There are currently 30,000 registered ECOBICI users. The system has reached capacity and there’s now a waiting list to sign up. ECOBICI riders take an average of 9,000 trips each day. So far, the system has recorded 1.6 million trips. And despite having a reputation as a tough town for cycling, Mexico City has only had three reported accidents requiring hospital assistance since ECOBICI began.

Now, Mexico City is actually a much greener place than its smoggy reputation would suggest. The city recently opened two electrified bus lines that run the length of Reforma and Insurgentes; they even run in physically segregated, contra-directional lanes, which means the lines are unobstructed even during the worst traffic jams. There’s a bikeway running through parts of Insurgentes, and a ride on the city’s Metro is just three pesos (around 25 cents), among the cheapest transit fares anywhere on earth.

In other words, Mexico City, which was once considered the most polluted major city on earth, has adopted a more aggressive policy on sustainability than most cities in the United States. It isn’t at all shocking that its leadership would be open to something like a bike share, even if Mexico City doesn’t seem like an obvious candidate for such a system. Meanwhile, the city’s notorious traffic creates an opening for some other, more experimental means of getting around, like a bike share. The mere existence of an alternative to driving and traditional public transportation helps explain the DC Bikeshare’s success. It turns out that Mexiquenos are as thrilled to have the option of not driving as Washingtonians are, even if Mexico City is an incomparably more hazardous environment for biking.