My guess is that most of Europe's population will sit out the 'car-free day'.
Isn't it curious that the car has only become widely criticised at the point that it became cheap enough to become a working class consumption good, as opposed to a middle class luxury item?
Notable that most pedestrianised areas are sinking into economic depression, as well as being dirty and underserviced, like London's Covent Garden area, or Birmingham's Princes' Street. -- Jim heartfield