The disclosure includes implementations for providing ground adjustment for an in-vehicle augmented reality system. A system may include a three-dimensional heads-up display unit (“3D HUD”) installed in a vehicle. The system may include a memory storing instructions that, when executed, cause the system to: determine a plurality of elevation values for a plurality of points on a road surface, where each elevation value is associated with a point from the plurality of points and describes the elevation of that point; identify a graphic for display on the 3D HUD, where the graphic is associated with at least one point from the plurality of points; determine which location of the 3D HUD is associated with the at least one point associated with the graphic; and display the graphic at the location of the 3D HUD so that the graphic superposes the point when viewed by a driver.