Basic Road Terminology

The land set aside for use as a street or highway corridor. Rights of way are purchased prior to the construction of a new road, and usually sufficient extra land is purchased for the purpose of building sound walls, retaining walls, storm water sewer systems and other mitigation features. Sometimes, rights of way are left vacant after the initial roadway facility is constructed to allow for future highway expansion.

A reflective sign is a sign that has retro-reflective sheeting to allow for easy visibility at night under the illumination of headlights. Nationally, older, non-reflective signs, including the bulk of button copy based signs, were mostly replaced with highly reflective signs. As a side effect of this transition, many states coupled replacements with the removal of sign lights to offset electricity and maintenance costs as newer reflectivity standards provide ample [...]

A recommissioned highway is one that has changed numbers, street names, or route designations. The roadway might remain unchanged, but it has been given a new name. An example is Interstate 84 through northeastern Connecticut. It was redesignated as I-86 in 1969 but recommissioned as I-84 in 1984.

The oldest road atlas in the United States, the Rand McNally road atlas was first issued in 1926. This first edition was fraught with errors, because it was based on an older, unimplemented version of the U.S. Highway System. The 1927 edition corrected these errors, and the atlas has been updated every year since then.

An overlap is where two or more numbered routes share the same alignment. These may also be referred to as a concurrency or cosigned route.

An over crossing is a bridge that carries a road, railroad, or pedestrian walkway across a freeway or other highway.

An optional lane is a lane that provides motorists with the option of either continuing straight ahead or exiting. These kinds of lanes are common with two or three-lane exits. Optional lanes are signed with Overhead Arrow Per Lane (OAPL) signs on expressways and freeways.

The left lane of the freeway is known as the "number one lane" or the "fast lane." This lane is reserved for the fastest moving vehicles, and should be used for passing only. The other lanes are numbered from left to right, so the right lane is the Number Two Lane on a four-lane freeway, and the Number Five Lane on a ten-lane freeway.