R.I. Gen. Laws § 31-1-21: Enforcement officers.

(a) “Police officer” means every officer authorized to direct or regulate traffic or to make arrests for violations of traffic regulations or the administrator of the division of motor vehicles and up to five (5) subordinates designated by the administrator under the provisions of § 31-2-3.

(b) “Proper officer” means for the purposes of chapters 1 — 50 of this title, any member of the state or municipal police, deputy sheriff, city or town sergeant, the administrator of the division of motor vehicles, or any subordinate appointed by the administrator of the division of motor vehicles under the provisions of § 31-2-3.