R.I. Gen. Laws § 39-11-11
All common carriers subject to this chapter shall, before engaging in business, file with the administrator and keep open to public inspection at its offices and terminals schedules showing all rates, fares, and charges for transportation of passengers, or property, between different points on its route or routes, and also between points on its own route and on the routes of other common carriers, when a through route and joint rate have been established. No intrastate aircraft common carrier shall accept or receive any person or property for transportation until the requirements of this chapter have been complied with, and no carrier shall charge, demand, collect, or receive a greater or less or different remuneration therewith than the rates, fares, and charges that have been legally established and filed with the administrator; nor shall any carrier refund or remit in any manner or by any device any portion of the rates, fares, and charges so established. The administrator is vested with the power and authority to supervise, regulate, and fix, alter, and determine just, fair, reasonable, and sufficient rates, fares, charges, and classifications. No order of the administrator affecting rates, fares, and charges shall issue except after notice and hearing on the same, and any interested party may appear and take part in any proceedings.
R.I. Gen. Laws § 39-11-11