Question: I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "The local government continuously strives for a reduction of massive traffic congestion, and has increased incentives for making a bicycle-friendly city. This includes North America's second-largest bicycle sharing system, EcoBici, launched in 2010, in which registered residents can get bicycles for 45 minutes with a pre-paid subscription of 300 pesos a year. There are, as of September 2013, 276 stations with 4,000 bicycles across an area stretching from the Historic center to Polanco. within 300 metres (980 feet) of one another and are fully automatic using a transponder based card. Bicycle-service users have access to several permanent Ciclovias (dedicated bike paths/lanes/streets), including ones along Paseo de la Reforma and Avenida Chapultepec as well as one running 59 kilometres (37 miles) from Polanco to Fierro del Toro, which is located south of Cumbres del Ajusco National Park, near the Morelos state line. The city's initiative is inspired by forward thinking examples, such as Denmark's Copenhagenization."?
Answer:
Who has 4000 operating units?