The primary contributor of skin color is the pigment known as melanin. The quantity of melanin in the skin varies based on genetic factors and is also dependent on the degree of sun exposure. Melanin is produced by specialized pigment cells known as melanocytes.
Average new tires used on cars typically start with 10/32 to 11/32 of original tread depth. Tires are considered worn out. In most States when they reach 2/32 of remaining tread depth. Ans 2 - Here in Canada (and I'm sure in many parts of the US ) we get a lot of rain.
Understand that the primary function of tread on a tire is to divert water from beneath the tire to improve traction and avoid hydroplaning on wet roads. Tires become unsafe when they're worn, and once the tread is down to 1/16th of an inch (1.6mm), the tire is no longer safe. 2. Look at the tread pattern.