There's so much great old, tiny Euro iron in that video: Renault 4CVs, Citröen 2CVs, Beetles, Mk I Ford Escorts, and so much more. And lots of DAFs. In fact, a surprising amount of DAFs. Which is the big key to what's going on here: a reverse race.
DAFs' early, crude CVTs do have the one big added bonus of allowing the cars to drive as fast backwards as forwards, which makes them reverse-racing kings.