Communications. – After a period in which it seemed that the railroad was to definitively give its driving role in the US economy to other means of transport (especially cars and planes), the introduction of faster trains with the substantial modernization of the network has relaunched the fortunes of this medium. Nonetheless, the streamlining involved the closure of some sections, so that the network complex was about 331,000 km long in 1975, 10% less than ten years earlier. The railway continues to accommodate a gigantic movement of goods, which in the last decade has expanded by more than a quarter, approaching 3.5 billion tonnes, while passenger traffic has contracted by more than 40%, around 272 millions of individuals a year.
The construction of the new San Lorenzo waterway for access to the Great Lakes involved a restructuring of the fleet of lakers and canallers, the vessels in circulation on most of the inland waterways (the special fleet of the Great Lakes today tonnes approximately 1,560,000 t) and substantial modernization works of lake landings and canals connected to the Great Lakes-San Lorenzo system; this has allowed for a massive increase in internal traffic: in the section between Montreal and Lake Ontario alone, the movement exceeded 50 million tonnes at the end of the 1970s.
The road network of the USA in 1977 exceeded 6 million km, 80% of which was asphalted; among them, 1,029. o00 km formed the complex of urban roads. There were also about 7,500 km of toll motorway sections (compared to 500 in 1940) and another 1,700 km were under construction. Traffic on this gigantic road network has reached a level that is unique in the world, powered by 143 million cars, of which over 114 million cars.
Maritime navigation, ports and air navigation. – After the Second World War, a large part of the US fleet, greatly strengthened during the war effort, proved to be inadequate or economically exuberant to face international competition on the freight market. This led to a drastic reduction of the total tonnage: as of 1977 there were approximately 4,500 ocean vessels in operation with a total gross tonnage of over 13.7 million tonnes, equal to less than 5% of the tonnage of the world maritime fleet (ten years previously the capacity was almost 23 million tons, equal to 18.5% of the world total).
The US-flagged shipping participates for about 6% in the movement of the Confederation’s ports, which in 1970 totaled more than 580 million tons. More than a fifth of this movement belongs to the port of New York alone (132 million tons of traffic in 1977, of which 60 of international movement); however, this port has lost its position of world supremacy, which is now far surpassed by the European port of Rotterdam (271 million tonnes). The rise of traffic in the ports of the Gulf of Mexico is spectacular, where oil tankers operating on national routes dock above all: New Orleans reaches nearly 100 million tonnes, mainly at embarkation; Houston hit 90 million, Baton Rouge hit 74 million. By comparison, the position of the Atlantic ports appears almost static despite the large amount of traffic: the Philadelphia system moves 49 million tons a year, 38 in Norfolk, 39 in Baltimore. On the Great Lakes, the opening of the San Lorenzo waterway has allowed great leaps forward at the major airports: traffic in Chicago has increased to 18 million tons, that of Duluth to 30 million.
The network of air connections in the USA has further intensified, assuming gigantic proportions: in 1971 there were 12,000 stopovers for aircraft and 154,000 civil aircraft; in the same year the US air fleet made 175 million flights on international lines and 156 million on domestic lines, with an enormous movement of passengers (245 billion passengers / km) and goods (8 billion t / km). This fleet is strengthened thanks to the introduction of a good contingent of supersonic aircraft, more and more capable, while the use of helicopters for short-haul flights is becoming more widespread (there were almost a thousand heliports in 1971).
Foreign trade. – While the direction of the main currents of international trade belonging to the USA has undergone limited changes, given the universality that characterizes the commercial relations of this economic power, a radical change has affected the consistency of inflows and outflows, since the constant and clear dominance of exports over imports was reversed in the late 1960s. The phenomenon is linked to the exceptional increase suffered in recent times by imports of raw materials and to the revaluation of these goods, facts which have had a very serious impact on the trade balance of payments in the USA. The main incoming items are precisely made up of raw materials (oil, newsprint, copper, semi-finished metal products), as well as from foodstuffs; the products of the mechanical industry (today in particular electronics, automotive and aeronautics) always prevail, followed at a long distance by chemicals and cereals. Almost a quarter of the traffic takes place with Canada and an almost similar share with Western Europe (especially with the Federal Republic of Germany), while a growing role belongs to Japan (10% of the total movement), which is mainly exporter of finished products on the US market.