HRS §291-8
No baggage sticking out past the sides of a passenger vehicle
This law says that if you drive or are in charge of a passenger car or truck, you cannot carry baggage or freight that sticks out past the sides of the vehicle. The rule is about keeping loads within the vehicle's width.
everyone
The statute, as written — Freight on motor cars; projection of, prohibited
It shall be unlawful for any person driving, operating, or in charge of any motor car or truck used for the transportation of passengers, to carry or permit to be carried any baggage or freight on the motor car or truck in such manner that the same or any part thereof projects beyond the extreme width of the motor car or truck.
LawTrove is not legal advice. The summary above is a computer-generated restatement — the authoritative text is the official version linked above.