Why do rubber tires grip the road?

The answer

Tire grip involves two types of friction. Mechanical interlocking occurs when soft rubber deforms into microscopic road surface textures, creating physical grip. Molecular adhesion occurs when rubber molecules form weak chemical bonds with the road surface that constantly break and reform. Counterintuitively, smoother tires (slicks) actually provide more grip on dry, smooth surfaces because they maximize the contact area for molecular adhesion. Treaded tires exist primarily to channel water away and prevent hydroplaning.