Page:America's Highways 1776–1976.djvu/536

 of the Permanent Executive Committee of the Pan-American Highway Congress in Mexico City in 1964, permission was obtained for the Bureau of Public Roads to undertake geophysical research studies of the alternate or Atrato route along the Caribbean Coast of Colombia. This route had always been considered impossible because of the extensive Atrato swamps.

The Darien Gap highway was cut through almost impenetrable swamps adjoining the Republics of Panama and Colombia.

Using a helicopter which could land engineers and equipment on the surface of the swamp, field investigations of the preselected routes were made. Visual examination of surface conditions was supplemented by peat sampler penetrations into the swamp.

Once the specific route had been recommended, a geophysical survey was made by using electrical resistivity methods along the route corridor across the swamp. A sufficient number of tests were made to indicate a reasonably stable sand layer could be anticipated at depths of about 20 to 36 feet below the swamp surface to confirm the feasibility that the highway could be built across the Atrato swamp and it would save 205 miles in length, about $115 million in cost, and 5 years in construction time.

The Atrato route was approved, and as a result of this breakthrough and tremendous saving, the entire Darien project received international publicity and support from the Organization of American States. The Darien Gap project was selected by the National Society of Professional Engineers as one of the top 10 engineering achievements in 1968.

The U.S. Congress authorized the initiation of construction on the Darien program by an amendment to the 1970 Federal-Aid Highway Act. This amendment provided that funds should be obligated and expended under the same terms, conditions, and requirements with respect to the Darien Gap Highway as were the funds authorized for the Inter-American Highway. The amendment authorized the appropriation of $100 million for the Darien Gap program.

Administration of FHWA interests in the project is under the direction of the Region 19 office in the Panama Canal Zone, with field supervision being handled from division offices in both Panama and Colombia. The entire route, except for 14 miles in Colombia, has now been designed or is under contract for final design, with construction well underway in Panama. It is anticipated that by 1982 the vision of many legislators, engineers, and highway administrators for a “land bridge” to connect the Americas may become a reality.

The Japanese attack on Pearl Harbor on December 7, 1941, and their closely following successes in the Pacific found Alaska, located on the great circle route between the United States and Japan, in a position highly vulnerable to attack.

On January 16, 1942, the President appointed a Cabinet Committee consisting of the Secretaries of Navy, War, and Interior to consider the necessity of and proper route for a highway to Alaska. In February, it was concluded that a highway was necessary and that it should fulfill two major requirements: 530