Road classification is the different typology of roads (based on the number of lanes, geometric design, road width, traffic) that exists within the road network of a territory. In general, all countries consider a first category of roads with national traffic and another category of secondary roads with regional traffic (between towns in the same region) or local traffic. With the appearance of dual carriageway roads at the beginning of the century, a new type of road appeared that would end up becoming the main axes of any developed country.

The United Nations Economic Commission for Europe carried out a registration program for major European routes that began in 1975. All countries that signed the treaty agreed to sign their roads containing routes of the network. License plates are common in all countries, with a green background with white letters and a license plate type.

Highways and highways

In Spain, highways and highways are characterized by:.

national highway

They refer to single two-way traffic lanes, with shoulders generally of 2 to 2.5 meters.

county road

Those with a single carriageway with 2 lanes usually have 3 on slopes for slow traffic.

Two-way traffic. Variable shoulders, depending on the region or orographic or specific to the terrain (<1.5 m), although they can measure twelve meters wide, (as in the REDIA plan), (Castilla y León Highway Network, for example). The CL-601 was the N-601 and in the sections where it is preserved it has such shoulders. Generally accesses at the same level.

They are usually classified into subtypes, according to the number of lanes, the size of shoulders, which defines their speed and their signage. They also tend to constitute not only the main regional network, but also part of the secondary one. They can be highways (M-45). Currently, they are the main regional routes. They usually connect provincial capitals with regional capitals, or with national roads or serve as a ring road to the main cities, generally constituting (regional M-604, it is not main, but secondary, for example), the main regional network. All of these roads belonged to the Ministry of Public Works, until the 1980s, except for those built after the transfer.