R.I. Gen. Laws § 31-15-15: Designation and posting of controlled-access roadways.

(a) The state traffic commission may, by resolution or order entered in its minutes, and local authorities may by ordinance with respect to any controlled-access roadway under their respective jurisdictions, prohibit the use of a roadway by pedestrians, bicycles, or other non-motorized traffic or by any person operating a motordriven cycle.

(b) The state traffic commission or the local authority adopting the prohibitory regulations shall erect and maintain official signs on the controlled access roadway on which the regulations are applicable and when so erected no person shall disobey the restrictions stated on the signs.