Japan has different standards and driving environment around kei cars (I'm going to use K-car going forward).

- Their top speed limit even on highways is 100kmh / 60mph

- K-cars have yellow license plates and yellow license plates are not allowed on highways

I have a memory of seeing one of the infamous white K-trucks on an interstate in Nashville and was gobsmacked. These cars are not rated for highway / interstates in Japan, let alone the U.S.

I'm not sure if the U.S. has a similar visible markings for farm vehicles to allow K-cars city road travel and deny interstate travel. If not, I agree they should be banned until some sort of classification is made and driver culture / knowledge is propagated.