The tread is generally an interlocking design with more voids than a street tread. All-terrain tires also almost always feature siping, or very small grooves cut into each tread block, for better grip on smooth surfaces and ice. This type of 4x4 tire offers good tread life, a quiet ride and very good on-road handling characteristics. These are a great choice for a vehicle that you use primarily on road, but want a bit more capability for occasional use off-road.
1) The BFGoodrich All-Terrain T/A KO is the iconic tire in this segment, being introduced in 1976 and enjoying a healthy market share over its life.
2) Other current examples include the Goodyear Wrangler SilentArmor, General Grabber AT2 and Pro Comp Radial All-Terrain.