On car-free days, people are encouraged to travel by means other than cars. Some cities, like Jakarta and Tehran, have weekly car-free days. Other such days are annual. World Car Free Day is celebrated on September 22. Organized events are held in some cities and countries.

The events, which vary by location, give motorists and commuters an idea of their locality with fewer cars. While projects along these lines had taken place from time to time on an ad hoc basis starting with the 1973 oil crisis, it was only in October 1994 that a structured call for such projects was issued in a keynote speech by Eric Britton at the International Ciudades Accessibles (Accessible Cities) Conference held in Toledo (Spain).