The semi-truck with the logo on the side
Mac Macs is a company that distributes hamburgers. A delivery truck baring the name and logo is seen in Dragon Ball GT: A Hero's Legacy, when an unnamed truck driver offers Goku Jr. a ride, only to steal the young boy's food and drive off when he leaves the truck for a bathroom break.
The name Mac Macs may be taken from the name of the popular McDonald's sandwich, the Big Mac. Additionally, the M's in the logo resemble the McDonald's Golden Arch logo. Coincidentally, McDonald's would later be one of the sponsors of Dragon Ball Z Kai in Japan.