Tires must have a visible tread of at least of an inch across the base.

Tires must have a visible tread of at least  2/32 of an inch across the base.

When changing tires you should not compromise safety by saving some money. Legally, in most countries the tire pattern must have a depth greater than 1.6 mm (European Union) or 2/32 inches (United States). With depths less than 3 mm, as this depth decreases, the grip of the tire on wet ground decreases, this decrease being much more pronounced when lowering 2 mm, significantly decreasing the speed at which the hydroplaning is reached (aquaplaning) and traction in snow it is almost nil.

answer; i believe that the correct answer is ( troxel v. granville);

can you explain it better