A tire is considered in safe operating condition when it is not subject to rejection or considered unsafe for any of the causes listed in Regulation .09 of this chapter. Inspection of Tires. Tires shall be visually inspected for: Bumps or bulges due to tread separation; Exposed ply or cord; Cord damage; and Tread depth. Tread depth shall be measured with a tread depth gauge or other suitable measuring device in any two or more adjacent tread grooves at three locations equally spaced around the circumference of the tire, at least one of which shall be at a point where the tread is thinnest exclusive of tie bars and tread wear indicators. Tread depth may be measured by visual inspection of the tread wear indicators when molded into the tire. Other tire inspection regulations are contained in COMAR 11.14.