A tire tread scanner drive-over unit is used to measure the tread depth and tire wear condition of a vehicle with two or four wheels on the axle. The unit includes a surface with two tire position area areas, each between an elevated rearward area and an elevated forward area to define a trough therebetween. Scanners are located behind scanner windows in the rearward area under scanner covers. When a vehicle is driven onto the surface so that the tires of one of its axels are on the tire position areas between the rearward and forward areas, the tires self-center against the scanner windows so that the tire profile may be measured to determine wear and wear characteristics.