INTERSTATE HIGHWAY FACTS

The Federal-Aid Highway Act of 1938 was the first serious
attempt to develop a national roadway system. Officials
studied the feasibility of a toll-financed system of three
east-west and three north-south superhighways.
They learned that this system could not be self-supporting, and advocated
for a 26,700-mile network instead.

                       

Congress passed further legislation in the form of the
Federal-Aid Highway Act of 1944. The act chartered a
"National System of Interstate Highways" and expanded the
network to 40,000 miles. Soon state highway agencies and
the Department of Defense planned nationwide routes. No
specific funds were authorized for construction, however,
making progress slow.


President Dwight Eisenhower was the one who finally made
the U.S. Interstate a reality. The Federal-Aid Highway Act
of 1954 set aside $175 million for the construction of an
interstate highway system. However, even more money was
needed for the system that Eisenhower envisioned, and he
continued to press for funds. Two years later, the expanded
Federal-Aid Highway Act of 1956 authorized a budget of $25
billion, of which the federal share was to be 90%.


The legislation of 1956 also provided for an extended
network of 41,012 miles and nationwide design standards,
including: a minimum of two lanes in each direction, lanes
that were 12 ft in width, a ten-foot right paved shoulder,
and design speeds of 50–70 mph.

                        

Further legislation over the years continued to expand the
total length of the system, which now stretches for more
than 46,726 miles. In 1990, in recognition of President
Eisenhower's pivitol role in building the national system
of interstate highways, President George Bush signed
legislation officially renaming it the Dwight D. Eisenhower
System of Interstate and Defense Highways.

                        

Major routes are designated by single- or two-digit numbers.
If a route runs north-south, it is given an odd number, and
if route a runs east-west, an even number. For north-south
routes, numbering conventions begin in the west. Thus I-5
runs north and south along the West Coast, while I-95 runs
north and south along the East Coast. For east-west routes,
numbers begin in the south.