Editing Interstate Highway System (section)

===Sign locations===
There are four common signage methods on Interstates:
* Locating a sign on the ground to the side of the highway, mostly the right, and is used to denote exits, as well as [[rest area]]s, motorist services such as gas and lodging, recreational sites, and freeway names
* Attaching the sign to an overpass
* Mounting on full [[gantry (road sign)|gantries]] that bridge the entire width of the highway and often show two or more signs
* Mounting on half-gantries that are located on one side of the highway, like a ground-mounted sign