"Letter" symbol marks the post office. Post this 24" x 24" sign for all mail carriers to see.
Standard: 01 Because regulatory, warning, and guide signs have a higher priority, acknowledgment signs shall only be installed where adequate spacing is available between the acknowledgment sign and other higher priority signs. Acknowledgment signs shall not be installed in a position where they would obscure the road users' view of other traffic control devices. 02 Acknowledgment signs shall not be installed at any of the following locations: On the front or back of, adjacent to, or around any other traffic control device, including traffic signs, highway traffic signals, and changeable message signs; On the front or back of, adjacent to, or around the supports or structures of other traffic control devices, or bridge piers; or At key decision points where a road user's attention is more appropriately focused on other traffic control devices, roadway geometry, or traffic conditions, including exit and entrance ramps, intersections, grade crossings, toll plazas, temporary traffic control zones, and areas of limited sight distance.