The U.S. Highway System was created in 1926 to replace the inconsistently marked and maintained auto trail system. It assigned a standardized marking system for routes that crossed state lines. The route numbering system was designed to be logical, with even-numbered routes traveling east-west and odd-numbered routes traveling north-south. The lowest numbers are in the east and north, and the highest numbers are in the west and south. Although the [...]
Unsigned routes can be one of two things: first, a highway may be primarily signed with one designation (such as a U.S. highway) but also carry another designation (such as a state route). These hidden designations include U.S. routes that silently merge onto an Interstate highway and hidden state route control numbers used by various departments of transportation throughout the country. An example is U.S. 87, which is the unsigned [...]
These are auxiliary routes of a U.S. or state route that is the preferred (or sometimes mandatory) route for commercial truck traffic. Such restrictions may be imposed because of weight or hazardous material restrictions on the primary route or because a community requested that commercial trucks be routed around their area. An example is Truck U.S. 19 in Pittsburgh, Pennsylvania.
A three-digit interstate or 3di is an Interstate Highway that acts as a loop, bypass, or spur from a main Interstate route (known as a one or two-digit interstate). Three-Digit Interstates that begin with an even number are generally routes around or through cities, and routes that begin with an odd number are generally routes that spur into cities or reach areas not located near the main Interstate. The term [...]
All four route classes utilize letter suffixes in some form across the United States. Cases for suffixed routes include the scenario where a highway divides into two alternative routes and neither route is considered to be the "main" route. U.S. 49E (east) and 49W (west) in Mississippi, where the east branch serves Greenwood and the west branch serves Indianola, is an example of this. Another instance occurs along state and [...]
Term used for a state-maintained road in most of the United States.
Term used for a state-maintained road in Florida, Indiana and New Mexico. Indiana uses the term interchangeably with state highway.
Term used for a state-maintained road in Wisconsin. Minnesota uses the simpler nomenclature of Trunk Highway. Michigan's state highway network is formally referred to as the State Trunkline Highway System.
Term used for a state-maintained road in Arkansas, Colorado, Idaho, Iowa, Kansas, Louisiana, Michigan, Mississippi, Montana, Nebraska, North Carolina, North Dakota, Oklahoma, South Carolina, South Dakota, Texas, Wyoming.
A spur route is a route from the mainline highway or freeway into a city or town. An example is Interstate 195 in Florida, which connects Interstate 95 in Miami with the city of Miami Beach. Georgia, Arkansas, Missouri, TExas and Virginia sign spur routes for U.S. and/or State Routes as local connectors between a parent route and another roadway or a community. South Carolina also incorporates spur routes, but [...]