Although some modern tires use computer-developed designs that can individualize tire areas with the noise treatment features, many designs use the noise treatment technique in the form of staggered tread blocks, such that design features are repeated in other areas of the tire. The examiner must locate every area of a tire that conforms to the design present in the questioned track and subject all of them to the same comparative examination. Tread-wear indicator bars are slightly raised areas at the bottom of the groove that run laterally across the tire tread to indicate when the tread has been worn to the extent that the tire should be replaced. In cases of excessive wear, the tread wear indicators will show as continuous bars across the tread design in both two-dimensional and depressed tracks. These can be valuable aids in locating an area for comparison. Tire sidewall markings will appear in depressed tracks and can be helpful in locating other tire class characteristics on a suspect tire. 1 table, 7 figures, 4 references.