R.I. Gen. Laws § 24-10.1-5

Any sign, display, or device lawfully in existence along the interstate system or the primary system on May 6, 1966 and which is not in conformity with the provisions contained in this chapter shall not be required to be removed until July 1, 1970. Any other sign, display, or device lawfully erected which does not conform to this chapter shall not be required to be removed until the end of the fifth year after it becomes nonconforming.