On car-free days, people are encouraged either through state policy or by societal consensus 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. In Israel, the holiday of Yom Kippur is regarded as a car free day through societal consensus without official policy enforcement.

The events, which vary by location, give motorists and commuters an idea of their locality with fewer cars. The concept dates from the 1970s but was popularised in the 1990s. Tel Aviv has had a car free day due to Yom Kippur since 1935.

Currently Bogotá holds the world's largest car-free weekday event covering the entire city. The first car-free day was held in February 2000 and became institutionalised through a public referendum.

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.

Within two years the first Days were organized in Reykjavík (Iceland), Bath (United Kingdom) and La Rochelle (France), and the informal World Car Free Days Consortium was organized in 1995 to support Car-Free Days worldwide. The first national campaign was inaugurated in Britain by the Environmental Transport Association in 1997, the French followed suit in 1998 as In town, without my car! and was established as a Europe-wide initiative by the European Commission in 2000. In the same year the Commission enlarged the program to a full European Mobility Week which now is the major focus of the Commission, with the Car-Free Day part of a greater new mobility whole.

In 1996, a Dutch action group, Pippi Autoloze Zondag, started a national campaign for car free days. Pippi organized monthly illegal street actions to take over the streets and stop the cars. After blocking the streets, there would be parties, picknicks, kids playing, rollerskate on the motorway, street painting and music artists playing. The police would break the party down and make arrests. Pippi went on to create a Dutch national group to fight for car free days. Pippi lobbied every single national parliament politician from the Netherlands and inspired Dutch national parties to adopt the concept of car free days in their agenda. Every major city government in the Netherlands received Pippi's proposals to implement car free days, forcing them to debate the issue. After two years of actions, several cities in the Netherlands relented and started to implement car free days.

The Environmental Transport Association set the initial annual Car-Free Day on the first Tuesday in their Green Transport Week (around 17 June). In 2000 it was agreed to make it a self-standing day held on September 22, originally as a pan-European day organised under the auspices of the European Commission and later with international extensions—during which a large number of cities around the world are invited to close their centers to cars. Pedestrians, bicycles, public transit and other forms of sustainable transportation are encouraged on these days. People can reflect on what their city would look like with a lot fewer cars, and what might be needed to make this happen. Advocates claim that over 100 million people in 1,500 cities celebrate International Car-Free Day, though on days and in ways of their choice.^{[citation needed]}

Also in 2000, car free days went global with a World Carfree Day program launched by Carbusters, now World Carfree Network, and in the same year the Earth Car Free Day collaborative program of the Earth Day Network and the World Car Free Days collaborative.