As “off-road” vehicles, mini trucks are legal to drive in all 50 states on most unpaved roads, in rural areas, and on private property. Some states allow on-road use as well, such as in Maine, where they can be registered as “low-speed vehicles” and can legally travel on public roads with a posted speed of 35 mph or lower. Welcome to Japan Mini Truck Parts. Available in 2WD or 4WD version, Japanese mini trucks are also known as Kei class trucks or simply Kei trucks. They are extremely versatile when it comes to applications. Japanese mini trucks are used in the US for agriculture, construction, firefighting, and many other off-road applications.