Tread wear bars appear when tires are worn down to __ inch of tread a) 1/16

Tread wear bars, also known as tire tread indicators, are raised sections within the tire's tread grooves that indicate the tire is worn down to a depth of $1/16$ inch. These bars are designed to provide a visual warning that the tire is worn and needs to be replaced soon. When the tire reaches this depth, it no longer provides adequate traction and can lead to reduced vehicle control and increased stopping distances. It is important to replace tires when the tread wear bars appear to ensure safety and proper vehicle performance.