The study resulted from recognition that such information may be useful when a positive identification of a tire or tires at a crime scene is impossible. The survey collected information from visual observation of the tires on 1,250 parked vehicles in parking lots of grocery and discount stores in Des Moines and several smaller cities, as well as parking at the State capitol and law enforcement impound lots. The vehicles included 858 passenger cars, 163 pickup trucks, 134 vans, and 95 sport utility vehicles. Results revealed that 72.3 percent of the vehicles had all four tires with the same tread design, 14.3 percent had two pairs of tires with each pair of matching tread design, 6.1 percent had three tread designs, 5.9 percent had a single mismatched tread design, and 1.4 percent had four tires of a different tread design. A total of 96.9 percent had all four tires of the same size, only 1 vehicle had tires of 3 different sizes, and no vehicles had 4 different-sized tires. Findings indicated that a significant majority of vehicles have four tires all with the same tread design and tread size. Findings were consistent with the results obtained in an earlier study in Florida. Tables, author contact information, and 4 references