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   The beginnings of Interstate Highway System, as we know it today, can be traced to the summer of 1919, when LTC Dwight D. Eisenhower served as an observer to the first transcontinental convoy.  Testing the endurance of vehicles and roads, the convoy took two months to travel from Washington DC to San Francisco.

   During Eisenhower's service in Europe during World War II, he witnessed the incredible efficiency of the German autobahns.

IKE in 1919

   When Eisenhower became president in 1953, one of his top priorities was an Interstate highway system.  In 1956, he signed the Federal Aid Highway Act that allocated $25 billion to the project.

IKE as president signing the Interstate Highway Act

The Interstate Project

   The Interstate project was to be completed by 1975 with a total of over 41,000 miles of interstate highways.  The standards for the project included:

    * Two lanes minimum in each direction

    * Lanes that were 12 feet in width

    * Right shoulder to be 10-foot wide and paved

    * Design that allowed speeds of 50-70 miles per hour

    * No intersections, traffic signals or rail crossings

   An estimated 55,000 bridges were built to accommodate the requirement for uninterrupted traffic flow.

map of Interstate system

It was “the greatest public works program in the history of the world.”


   The American Association of State Highway Officials (AASHO) was responsible for all testing.  The official test began in November 1958 and was completed in December 1960.

testing the interstate construction standards

After the ribbon-cutting, the first trucks roll over Loop 6.

    They tested asphalt and Portland cement pavement on all base soil types, construction techniques, and other roadway standards.   They also tested axle loads and gross vehicle loads on all pavement types and bridges. 

design of test track for interstate

   Special military vehicles and highway construction equipment were also included in the test.

   Over the 25-month period, Transportation Corps trucks and crews drove 25-35 mph over 17 million miles on the six test loops.

    The importance of the Interstate for military transport was critical.   The Department of Defense closely monitored all phases of the testing. 

   During World War I, roads throughout the country were nearly destroyed by the weight of military trucks.

   During World War II, 13% of the defense plants received all their supplies by truck, and almost all other plants shipped more than half of their products by vehicle.  Also discovered was a bewildering array of standards - some states allowed trucks up to 36,000 pounds, while others restricted anything over 7,000 pounds.

testing underway

   They began with 81 vehicles, increasing as the test evolved.  The average day was 18 hours, including 14 hours driving and 4 hours maintenance and driver changes.

heavy load test

Vehicle with extra heavy load during a test-to-failure with increasing loads.

Interstate Highway System

   Construction began in 1956 and ended in 1980, with additions and improvements still on-going.  Today, the interstate spans 46,380 miles of the United States, and costs roughly $58.5 billion.

construction on actual interstate in 1956

Construction began in 1956 on Interstate I-70 in Missouri and Kansas.

   In August 1957, AASHO announced the numbering scheme for the Interstate.  North and South highways were given odd numbers, beginning in the west.  East and West highways were given even numbers, beginning in the south.  Connecting routes around cities were assigned three-digit numbers.

various Interstate signs

   The familiar red, white and blue interstate shield was a combination of designs submitted by Missouri and Texas.

Interesting Interstates


I-70 in Colorado

   Colorado's I-70 through Glenwood Canyon includes over 40 bridges, viaducts, and several roadways on top of one another to preserve space in this beautiful canyon.  It also includes a tunnel passing through the continental divide.

I-75 Alligator Alley in Florida

 Florida's I-75, nicknamed Alligator Alley, includes underpasses for panthers and other wildlife to pass freely underneath to avoid disrupting their habitat.

I-90 in Seattle

Seattle's I-90 required lower areas for bridges and land coverings, and the landscape called for an extremely unique floating bridge.

    The initial purpose of the Interstate was to allow for mass evacuation of cities during a nuclear attack.  It was also designed so that one mile in five was straight, useable as an airstrip in times of war or other emergencies.

an interchange in Harrisburg, Pennsylvania

A complicated interchange in Harrisburg, Pennsylvania

    One of the primary reasons for building the Interstates was national security.  The military benefits are as initially intended – to protect and defend our country.

Much of the success of Operation Desert Storm was due to our logistical ability      to rapidly move troops to theater.  The US highway system supported the mobilization of troops and moved equipment and forces to US embarkation ports – the was KEY to successful deployment.”

                                                Lt Gen Kenneth Wykle

                                                Deputy Commander in Chief

                                                US Transportation Command

 The economic benefits alone have been astounding.   Business development and employment opportunities have increased.  Housing has expanded as well as improved access to health care.  All citizens have greater mobility and broader vacation options.

    The Interstate has become the backbone of the world’s strongest economy,  and was designated by the American Society of American Engineers as one of the Seven Wonders of the United States.  This list also includes the Golden Gate bridge, Hoover Dam and the Panama Canal.

the official sign of the Interstate System







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