No local authority shall erect or maintain any stop sign or traffic control signal at any location so as to require the traffic on any state highway to stop before entering or crossing any intersecting highway unless approval in writing has first been obtained from the state traffic commission.
State approval for traffic control devices on state highways
R.I. Gen. Laws § 31-12-14., under Chapter 31-12 Applicability of Traffic Regulations.
R.I. Gen. Laws § 31-12-14.