Other good italian satires of the '60:
"I mostri"http://www.imdb.com/title/tt0057323/?ref_=nm_flmg_dr_44;
"La donna scimmia" http://www.imdb.com/title/tt0057006/?ref_=nm_flmg_wr_27;
"Divorzio all'italiana" http://www.imdb.com/title/tt0055913/?ref_=fn_al_tt_1;
also "Amici miei" http://www.imdb.com/title/tt0072637/?ref_=nm_flmg_wr_1 (even if that's from the '70's).
this film has basic story of Il Sorpasso:
Zorba the Greek (1964)
http://www.imdb.com/title/tt0057831/?ref_=nv_sr_1
I disagree. Il Sorpasso is a road movie, none of that is seen on Zorba. There are some similarities, like Zorba being a carefree guy who lives for the moment in contrast to a "square" guy. But tons of movies have such contrasts, that doesn't make them similar to Il Sorpasso.
There's an American version (broadly speaking) of Il Sorpasso, called "Your three minutes are up." Starring Don Leibman and Beau Bridges, realeased in 1973. It's available on Youtube!
Colpo gobbo all'italiana (1962) is great too! It's on Youtube with Italian subtitles (CC). If I watch it on my laptop, YT has the option to translate the subtitles. But if I use the YT app in my BlueRay DVD players, such option is not available.
Sideways (2004) is not Italian but I hear that is somewhat similar to Il Sorpasso.
https://en.wikipedia.org/wiki/Sideways