Troopers at the scene say the other driver was intoxicated, and WTOC crews witnessed that driver being taken into custody.
Tuesday is St. Patrick's Day, but many people were out celebrating over the past weekend.
Police say Officer Kaleb Bethel-Dean was found in a crashed vehicle with signs of impairment and refused a breathalyzer test.
The Cranston officer was arrested in Coventry for suspicion of DUI.