Abstract: A grinding wheel assembly for grinding grooves into road pavement has a rotating wheel with a plurality of parallel tracks spaced around the periphery of the wheel. A number of blocks are removably secured to the tracks of the wheel. Bits are removably secured to the blocks in a predetermined pattern to grind parallel grooves in the road pavement as the wheel rotates and the assembly moves along the road pavement. The bits on each block are arranged in a predetermined pattern so that bits on adjacent blocks are not aligned to hit the same groove in the road pavement, but bits on selected non-adjacent blocks are aligned to hit the same groove in the road pavement during rotation of the wheel. Preferably, the bits have a conical, polycrystalline diamond tip and a cylindrical base.