Figure 7 Is a plot of deflection basins that was obtained from Dynaflect measurements made on the South Dakota Test Pavements, Pierre, South Dakota. Readings were taken at one foot intervals (which is the normal geophone spacing) on asphaltic concrete thicknesses ranging from three to twenty-four inches at three inch increments. The marked changes in the basins at each of the three inch 7 Increments can be noted.