What are the official guidelines that determine when a stop sign is warranted?

The Rhode Island Department of Transportation (RIDOT) requires that all cities and towns follow the national guidelines outlined in the "Manual on Uniform Traffic Control Devices" (MUTCD) in determining the use of traffic control devices, including STOP signs:

The purpose of the stop sign is to prevent collisions. It is not intended, nor shall it be used for the control of speed, traffic calming, or to forestall pedestrian, rear-end, or turning movement accidents.

To insure uniformity in stop sign studies and recommendations, the warrants as provided in the 2009 MUTCD. Section 2B.05 will govern.

Multi-way stop Signs must meet the warrant criteria as outlined in Section 2B.07 of the 2009 MUTCD.