It's not just an American thing. "6. Drivers must not drive at such a low speed that they constitute an obstruction or danger to the normal flow of traffic." [

It's not just an American thing. "6. Drivers must not drive at such a low speed that they constitute an obstruction or danger to the normal flow of traffic." [machine translated] https://www.aci.it/i-servizi/normative/codice-della-strada/titolo-v-norme-di-comportamento/art-141-velocita.html https://www.aci.it/i-servizi/normative/codice-della-strada/t...