State Map Route Markers
In the United States, in addition to the Interstate Highway System (previously on Cartophilia here, here and here) each state maintains its own system of highways.
State highways are generally a mixture of primary and secondary roads, although some are freeways. Each state has its own system for numbering and signage. Some states (the really lame ones) use simple square or circular designs. Others use a symbol that is associated with that state (see Pennsylvania's Keystone State design). The coolest states, however, are the ones that use a map on their State Route signage.
Besides the four shown here, the other cool state highway systems are: Alabama, Arizona, Arkansas, Georgia, Idaho, Nevada, Oklahoma, South Dakota, Tennessee and the District of Columbia. Of course, Wyoming and Colorado could be using their state shape... and who would know?
Take a Sporcle quiz to see if you can identify more State Route highway signs than your cubemate.
You can even order your own State Route sign (standard reflective or high intensity!) with the highway number of your choice.
In case you were wondering, Montana has the longest State highway route.
The best part about State map route signs: There is never a question which state you're in.