|Location Map ( geo)|
With over 3000 km of autoestradas – the vast majority of which have been constructed since 1990 – Portugal has one of the most extensive motorway networks per head of population in western Europe. It is supplemented by vias rápidas, long-distance single-carriageway roads, usually S2 or S2+1, with infrequent and occasionally grade-separated junctions and lacking steep hills and severe bends. The country also has an extensive network of minor roads, which vary widely in width, standard, and level of maintenance.
Portugal's national road network is defined by the Plano Rodoviário Nacional (National Road Plan, abbreviated to PRN), most recently updated in 2000. The national network is divided into a Rede Fundamental (Principal or Fundamental Network) and a Rede Complementar (Additional or Complementary Network).
The Rede Fundamental consists of nine routes referred to as itinerários principais (principal itineraries), numbered IP1-IP9. The Rede Complementar consists of 37 routes referred to as itinerários complementares (complementary itineraries), numbered IC1-IC37, along with a number of estradas nacionais (national roads), which are numbered with an EN prefix.
The network of IP and IC roads overlaps the motorway network, which is numbered separately with an A prefix, meaning that almost all of Portugal's motorways technically have two numbers. In practice, however, only the Ax number is signed, while IPx and ICx numbers only appear on signs on non-motorway sections. EN route numbers are signed as Nx; their numbering system is a hangover from the 1945 PRN (see below). Many sections of EN roads from that plan retain their number and use as local routes, despite not featuring at all in the current PRN. Some of these are theoretically superseded by unbuilt sections of IP or IC routes.
Some sections of former EN roads are included in the current PRN, downgraded to estradas regionais (regional roads). These have the same road number as the former national road, but with the prefix ER in place of EN. Two lower classifications of road exist - these are estradas municipais (municipal roads) and caminhos municipais (municipal paths), numbered with EM and CM prefixes respectively. These are managed on a local level.
Classification of roads in Portugal dates back to the 19th century, but was piecemeal and unclear until an official classification was established in 1926. This divided roads into estradas nacionais (national roads), estradas municipais (local roads) and caminhos públicos (public paths), the latter two managed by municipal government. The national roads were further divided into first and second class, numbered Nxx-1 and Nxx-2 respectively. Route numbers generally increased from north to south.
This classification was reformed with the publication of the first PRN in 1945, which introduced the terminology of Rede Fundamental and Rede Complementar. The former consisted of 18 itinerários principais (principal routes) numbered N1-N18, 25 further 1st class roads numbered N101-N125 and 70 2nd class roads numbered N201-N270. The latter consisted of 98 3rd class roads numbered N301-N398, plus 438 spurs which took the number of the road they branched from followed by a hyphen and the number of the spur (for example the third spur off the N16 was numbered N16-3). As before, route numbers generally increased from north to south, with the exception of the itinerários principais which were numbered based on the importance of the route. The route prefix N was also modified to EN, but was (and remains today) maintained as N on signage.
The modern designations of itinerários principais and complementares were introduced in the 1985 version of the PRN. The network of EN routes, with the exception of those upgraded to IP or IC, was included only as "other roads". In practice, most of these continued to be signed as they were in 1945, a practice which continues to this day.