Mailbox Installation Guide

Mailbox installation may seem simple, but residents need to think about safety before they install a new mailbox. Mailboxes that are set firmly into the ground, and/or have large posts, can become a fixed-object hazard. Mailboxes that are not fixed properly to their support can break loose and become dangerous projectiles, endangering motorists and residents. When installing a mailbox, residents should look at a few issues before selecting a location. Safety and convenience of both the mail carrier and the patron must be addressed. A mailbox should not be installed where a person will have to walk along the shoulder of a road for more than 200 feet.

The mailbox should also be located in an area visible to motorists, but should not be placed too close to the roadway or the usable shoulder. It should be placed on the right side of the road in the direction that the postal employee is traveling and on the far side of the patron's driveway. The U.S. Postal Service has regulations for mailboxes and mailbox height. It does not have any regulations regarding mailbox installation. The U.S. Postal Service only approves certain mailbox types and requires that the bottom of the box be 42 to 48 inches above the ground. This height is at windshield level, and is the main reason for having the mailbox firmly attached to the post. A mailbox that becomes unattached can break through the windshield of a vehicle and possibly injure the occupants. The mailbox should be approved by the U.S. Postal Service, and should be as lightweight as possible. No more than two mailboxes should be fastened to the same support, and a distance equal to three-quarters the height of the mailbox should be left as a space between the boxes.

The mailbox should be attached to the support firmly to prevent it from coming off and possibly injuring motorists and residents. Improper support systems, such as concrete or sand-filled containers, and thick metal pipes, can be hazardous to motorists. Support should be made of lightweight materials that will easily break away. If metal pipes are used, the pipe should not have a diameter greater than two inches. Wood posts should not be greater than four inches square, or have a diameter of more than four-and-one-half inches. The post should not be more than 24 inches into the ground and should not be set in concrete. By following these guidelines, the mailbox post will either break or be moved rather than be a safety hazard for motorists and residents. Before installing a mailbox, residents should contact the local permit department to determine if there are any mailbox ordinances in their community.

Take a look at a video created by the RCOC on mailboxes.

More Information

The American Association of State Highway and Transportation Officials (AASHTO) has published a guide for mailbox location and assembly titled, "A Guide For Erecting Mailboxes on Highways." AASHTO can be contacted at:
American Association of State Highway and Transportation Officials
Suite 225
44 North Capitol Street, NW
Washington, D.C. 20001
Phone: 202-624-5800

Provided by:
Traffic Improvement Association
2709 South Telegraph Road
Bloomfield Hills, MI 48302
Phone: 248-334-4971