R.I. Gen. Laws § 31-27-6: Lanes of operation.

(a) Any bus, commercial vehicle, camper, vehicle registered as a camper, trailer, or vehicle carrying a camper or trailer traveling on Rhode Island interstate highways shall be allowed to travel only in the first two (2) right hand lanes, except in cases of left hand exits, in which case the vehicle shall be allowed to enter the third and fourth left hand lanes one mile prior to an exit.

(b) For the purpose of this section, “commercial vehicle” means any vehicle registered for commercial purposes and designed and used primarily for the transportation of goods, wares, or merchandise. “Bus” means any vehicle designed for carrying ten (10) or more passengers and used primarily for the transportation of persons.

(c) The provisions of this section shall only be effective during the period that official traffic signs are in place to notify operators of the provisions of this section. Any persons violating the provisions of this section upon conviction shall be fined not more than one hundred dollars ($100).