the invention for example if only a single cutting wheel 40 is employed then the motion of the apparatus 10 in a forward direction along the road would necessarily be slower for the same spacing between grooves as above noted the central utility of the apparatus is to permit the continuous formation of grooves without stopping the truck which carries the apparatus in order to make the grooves it will be apparent that the curvature of each individual groove will depend upon both length of shafts 44 as well as the forward speed of the vehicle along the road the direction of rotation of axles 44 and housings 46 about shaft 32 may be clockwise or counter clockwise as viewed in fig1 as seen from fig4 for any given direction of rotation of vertically extending shaft 32 the direction of rotation of any right hand cutting wheel 40 as it commences its cut into the road edge 62 will be the same this follows by action of the drive of the shafts 44 from power input shaft 32 and bevel gears 45 and 47 after the completion of the formation of grooves 140 they may be coated with a light reflecting material or substance such as paint laden with glass reflecting particles or spheres rain will run off and thus not collect on the slanted walls of the grooves the water will run off the groove sides and out of the groove bottoms to the road edge and onto the shoulder 64 accordingly the light reflective material on the.