In 1989, Mexico City introduced Hoy No Circula, “today it does not drive.” The program bans most drivers from using their cars one weekday a week, according to the last digit of the license plate. Chilango writes that “mucha gente, que no quería quedarse sin coche, optó por comprar un auto extra, aunque fuera viejito” (many people, who did not want to be left without a car, chose to buy an extra one, even an old one).
In 2008, Lucas Davis published a study of the program in the Journal of Political Economy. He reports that evidence from additional sources indicates that the restrictions led to more vehicles in circulation and to a shift toward high-emission vehicles.