Pan American Highway, a system of highways linking the republics of North and South America. When completed, the Pan American Highway will run some 20,300 miles (32,700 km) through Canada, the United States, Mexico, Central America, and South America. The Pan American Highway, together with various alternate and connecting routes, forms part of a network of highways called the Pan American Highway System that will link Alaska (via the Alaskan Highway) with the southern tip of South America.
The Pan American Highway is neither a single road nor part of a centrally administered road-building program. Consisting of roads that often follow long-established routes, the highway stems from a cooperative plan in which each country has jurisdiction to designate, maintain, or build its part. The chief coordinating body is the Pan American Highway Congress, which meets once every four years.
Except in Central America, where United States aid has been heavy, each republic finances its road-building program. International agreements concerning the highway have dealt mainly with international connecting points, the financing of bridge construction at borders, and reciprocity of drivers' licenses and vehicle registration.
The Inter-American Highway is the name given to the portion of the Pan American that runs from the northern border of Mexico into Panama. It connects Mexico City and all the Central American capitals except Tegucigalpa, Honduras, and Belmopan, Belize. Although narrow, often steeply graded, and winding, the road is largely paved.
Extending across the border between Panama and Colombia is the Darién Gap, a large swampy jungle through which the Pan American Highway has yet to be completed. To continue to South America, vehicles must be ferried from Panama to La Guaira, Venezuela, or Buenaventura, Colombia.
South America's section of the highway crosses mountain ranges in Venezuela, Colombia, and Ecuador before reaching the Pacific coast in Peru. Running southward, often through vast desert tracts, to central Chile, it turns eastward, crosses the Andes, and continues to the Rio de la Plata on Argentina's Atlantic coast. From there it runs northward through Uruguay into Brazil. There are also routes to Bolivia and Paraguay.
Along the highway are such capitals and major cities as Brasília, Rio de Janeiro, and Sāo Paulo, Brazil; Montevideo, Uruguay; Buenos Aires, Argentina; and Asunción, Paraguay. On the Pacific side are Santiago, Chile; La Paz, Bolivia; Lima, Peru; Quito, Ecuador; Bogotá, Colombia; and Caracas, Venezuela.
Road conditions vary greatly. In some areas, especially near large cities, the highway is carefully graded and well paved. In some remote areas it is nothing more than a rough gravel road, and a few sections are impassable during part of the year. In many areas the route is poorly marked with road signs and there are few facilities for eating, sleeping, or repair.
The Pan American Highway was proposed in 1923 at the Fifth International Conference of American States, meeting in Santiago, Chile. Two years later the Pan American Highway Congress was created as a permanent institution to foster the building of the road. Routes were tentatively selected and plans were drafted, but only modest progress was made in construction until a final agreement was reached by the member states in 1936.
World War II brought increased interest in the United States for a highway south to the Panama Canal. Mexico completed its section of the Inter-American in 1950. The rest of the Inter-American, built largely with United States aid, was opened to through traffic in 1963.