The principal purpose of guide signs is to direct travelers to their destinations by the best route. However, it is not feasible to install signs listing all of the possible destinations that may be reached from the highway.
Drivers must be expected to make reasonable preparation for locating their destination and to have information that is readily available on road maps.
Determining Guide Sign Messages
Simplicity and clarity are necessary because drivers of moving vehicles are unable to read lengthy or complicated messages on signs. For this reason, the number of lines on a sign is kept to a minimum, and should not exceed 3. On freeways, high traffic speeds demand that the number of signs be limited to absolutely essential for the guidance of the motorist. Freeway exits are identified by exit number, the route number or by the name of the intersecting road. Certain additional messages may be provided where justified.
In rural areas signs may be installed to direct travelers to services such as roadside rests, gas, food, and lodging.