The main purpose of post mounted signs is to control and direct traffic. The signs that IRM normally install are either mounted on posts, such as U-channel breakaway posts, or wooden posts mounted in sleeves dug into the ground, or attached to an existing structure, such as a mast arm or building.

Most signs installed on DOT right-of-ways are taken directly from the sign regulatory and must conform to State sheeting, color and size requirements. Signs installed for private driveways, parking lots or developments can be taken from either the DOT regulatory or can be "customized" to get your message across.