A police officer arrested Bertine (D) for driving his van while under the influence of alcohol. After D was taken into custody but before a tow truck arrived to take the van to an impoundment lot, another officer, acting in accordance with police procedure, inventoried the van's contents. Included in this inventory were the contents of a backpack found in the van. The backpack search yielded various controlled substances, cocaine paraphernalia, and a large amount of cash. D objected to this search. The court determined that the search did not violate his rights under the U.S. Constitution, but it violated his rights under the Colorado (P) State Constitution. The Colorado Supreme Court affirmed but premised its ruling on the Federal Constitution. The United States Supreme Court granted certiorari.