Tread wear close to wear mark

Any brand of tire will have a wear mark at the bottom of the tread groove. General car tires wear mark height of 1.6 mm (this is also the legal minimum groove depth) , truck tires wear mark height of 2.4 mm. 

Some car owners think that as long as the tire is not broken, even if the tire pattern is nearly worn out, such an old tire is actually very dangerous: When the wet slippery road, tread pattern can not completely drain the water under the tire, it could easily cause the car to lose control.