Type 1 object marker is either a marker consisting of nine yellow retroreflectors, each with a minimum diameter of 3 inches, mounted symmetrically on a yellow (OM1-1) or black (OM1-2) 18-inch diamond; or on an all-yellow 18-inch retroreflective diamond (OM1-3). Type 2 object marker is either a marker (OM2-1V or OM2-1H) consisting of three yellow retroreflectors, each with a minimum diameter of 3 inches arranged either horizontally or vertically on a white panel measuring at least 6-inch x 12 inches or on an all-yellow horizontal or vertical retroreflective panel (OM2-2V or OM2-2H), measuring 6-inch x 12 inches. Type 3 object marker is either a striped marker measuring 12 x 36 inches, consisting of a vertical rectangle with alternating black and retroreflective yellow stripes sloping downward at an angle of 45 degrees toward the side of the obstruction on which traffic is to pass. The minimum width of the yellow and black stripes shall be 3 inches. OM-3L object marker has diagonal stripes oriented from the top left to lower right. OM-3R object marker has diagonal stripes oriented from the top right to lower left. OM-3C object markers have diagonal stripes oriented from the center to the left and right.