| Federal Highways | |
| Caption: | One-, two-, three-digit, and letter designation shields and tollway shield |
| Map: | File:Map of Mexican Autopista Network.png |
| Maint: | Secretariat of Communications and Transportation |
| Header5: | Highway names |
| Label1: | Federal Highway: |
| Field1: | Federal Highway X (Fed. X) |
| Country: | MEX |
| Type: | FH |
Federal Highways (Spanish; Castilian: '''Carreteras Federales''') are a series of highways in Mexico. These highways link Mexico's 32 federal entities with each other or with a neighboring country, and they are wholly or mostly built by Mexico's federal government with federal funds or through federal grants by individuals, states, or municipalities.[1] Locally known as federal highway corridors (Spanish; Castilian: los corredores carreteros federales), they are built and maintained by Mexico's Secretariat of Communications and Transportation (Spanish; Castilian: Secretaría de Comunicaciones y Transportes|links=no, SCT). Federal Highways in Mexico can be classified into high-speed, limited access expressways (usually toll highways that may be segmented and are marked by the letter "D") and low-speed roads with non-limited access; not all corridors are completely improved.
See main article: List of Mexican autopistas. High-speed expressways, known as autopistas or carreteras de cobro, are limited-access toll roads with controlled interchanges. Access to these roads is generally prohibited for pedestrians and animal-drawn vehicles, and fences are located at the side of the road for most of the length. Autopistas are highways with four or more defined lanes. Supercarreteras are toll roads with only two lanes, and they are found in mountainous areas. These tolled expressways typically have a corresponding non-limited-access road adjacent to them as a free alternative. In this system, the tolled road is signified by the word Cuota (toll), and the free road by the word Libre (free). The maximum speed limit is normally 110km/h for cars and 95km/h for buses and trucks. In some cases, the maximum speed can be 120km/h.[2]
Low-speed roads, known as carreteras, comprise the majority of the roads in this system. Some of these roads are divided highways with four or more lanes, often single-carriageway roads which have been converted into dual carriageways by building an adjacent carriageway next to the existing one. These roads are free of charge, and in most cases, two-lane highways that connect almost all of Mexico. These roads have interchanges at major roads, but most of these intersections are at grade. The maximum speed limit is 100km/h for cars and 95km/h for buses and trucks.
North–south highways are assigned odd numbers, while east-west highways are identified by even numbers. The start of the numbering system is located in the northwest of the country.
There are two exceptions to the numbering system: