A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually either a road numbered by the state or province, falling below numbered national highways in the hierarchy (route numbers are used to aid navigation, and may or may not indicate ownership or maintenance); or a road maintained by the state or province, including both nationally numbered highways and un-numbered state highways. Depending on the state, state highway may be used for one meaning and state road or state route for the other.
In some countries such as New Zealand, the word "state" is used in its sense of a nation. By this meaning a state highway is a road maintained and numbered by the national government rather than local authorities.
Australia's State Route system covers urban and inter-regional routes that are not included in the National Route or the National Highway systems. These routes are marked with a blue shield. Sometimes a state route may be formed when a former national route is decommissioned.
Most states and territories have introduced an alphanumeric route numbering system, either completely or partially replacing the previous systems.
Brazil is another country that is divided into states and has state highways.
Canada is divided into provinces and territories, each of which maintains its own system of provincial or territorial highways. Canada's federal National Highway System is a dual federal–provincial system which includes the Trans-Canada Highway network, and which has no uniform designation across the country.
Italy's Strade Statali extend for some 18,000 km, overseen by the Azienda Nazionale Autonoma delle Strade (ANAS) founded in 1946, replacing the A.A.S.S. (Azienda Autonoma delle Strade Statali) of 1928.
Mexico's State Highway System is a system of urban and state routes constructed and maintained by each Mexican state. The main purpose of the state networks is to serve as a feeder system to the federal highway system. All states except the Federal District operate a road network. Each state marks these routes with a white shield containing the abbreviated name of the state plus the route number.
New Zealand's state highway system is a nationwide network of roads covering the North Island and the South Island. As of 2006, just under 100 roads have a "State Highway" designation. The NZ Transport Agency administers them. The speed limit for most state highways is 100 km/h, with reductions when one passes through a densely populated area.
The highways in New Zealand were originally designated on a two-tier system, national (SH 1–8) and provincial, with national highways having a higher standard and funding priorities. Now all of them are state highways, and the network consists of SH 1 running the length of both main islands, SH 2–5 and 10–58 in the North Island, and SH 6–8 and 60–99 in the South Island. National and provincial highways are numbered approximately north to south. State Highway 1 runs the length of both islands.
Local highways (Hangul: 지방도; Hanja: 地方道; RR: Jibangdo; MR: Chipangdo) are the next important roads under the National highways. The number has two, three, or four dights. Highways with two-digit numbers routes are called State-funded local highways.
State highways are generally a mixture of primary and secondary roads, although some are freeways (for example, State Route 99 in California, which links many of the cities of the Central Valley, Route 128 in Massachusetts, Ronald Reagan Cross County Highway (State Route 126) in Cincinnati, or parts of Route 101 in New Hampshire). Each state has its own system for numbering and its own marker. The default marker is a white circle containing a black sans serif number (often inscribed in a black square or slightly rounded square), according to the Manual on Uniform Traffic Control Devices (MUTCD). However each state is free to choose a different marker, and most states have. States may choose a design theme relevant to its state to distinguish state route markers from interstate, county, or municipal route markers.