ment formula in which land area, road mileage, and population are factors. But some sections of the primary system are more important than others, from the viewpoint of the national interest. Consequently, in 1944 the Congress authorized the selection of a special network, not to exceed 40,000 miles in length, which in the language of the act would be so located as “to connect by routes, as direct as practicable, the principal metropolitan areas, cities, and industrial centers, to serve the national defense, and to connect at suitable border points with routes of continental importance in the Dominion of Canada and the Republic of Mexico.”
The result was the creation of the national system of interstate highways embracing about 1.2 percent of total road mileage, joining 42 State capital cities and 90 percent of all cites over 50,000 population. The interstate system carries more than a seventh of all traffic, one-fifth of the rural traffic, serves 65 percent of the urban and 45 percent of the rural population, and is the key network from the standpoint of Federal interest in productivity and national defense. Approximately 37,600 miles have been designated to date; the remaining 2,400 miles are reserved for future additions. This system and the mileage referred to are included within the Federal-aid primary system described above.
CIVIL DEFENSE ASPECTS
From the standpoint of civil defense, the capacity of the interstate highways to transport urban populations in an emergency is of utmost importance. Large-scale evacuation of cities would be needed in the event of A-bomb or H-bomb attack. The Federal Civil Defense Administrator has said the withdrawal task is the biggest problem ever faced in the world. It has been determined as a matter of Federal policy that at least 70 million people would have to be evacuated from target areas in case of threatened or actual enemy attack. No urban area in the country today has highway facilities equal to this task. The rapid improvement of the complete 40,000-mile interstate system, including the necessary urban connections thereto, is therefore vital as a civil-defense measure. Responsibility for selecting the highway facilities needed for this defensive action has been delegated by Executive order to the Bureau of Public Roads.
III. Why the System Is Inadequate
THE TRAFFIC JAM
Reduced to its simplest terms, the highway problem is this: Traffic has expanded sharply, without a corresponding expansion in capacity of roads and streets. As a result, a major portion of our facilities are seriously overcrowded. Moreover, this movement is faster and heavier than in previous years, and continues to increase.
Simple arithmetic illustrates the dimensions of the task. We now have more than 58 million motor vehicles registered—one for every 700 feet of every lane in both directions on all streets and highways in the Nation. This gigantic fleet traveled an estimated 557 billion vehicle miles in 1954, much of it concentrated on main arteries in urban areas which have become the expensive, hazardous bottlenecks referred to by the President.
