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American Scientist
the magazine of Sigma Xi, The Scientific Research Society
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Engineering
On the Road
Henry Petroski
I
n 1919 Dwight D. Eisenhower,
then a young lieutenant colonel
in the U.S. Army, rode in a convoy of
military vehicles that traveled from
Washington, D.C., to San Francisco. It
was the service’s first transcontinental
journey by motor vehicle, and the purpose of the exercise was to promote
the army’s Motor Transport Corps
and demonstrate its defense mobility.
Almost 300 enlisted men and officers
rode by motorcycle, car and truck in a
caravan that stretched for three miles.
Vehicles were draped with bunting of
red, white and blue, and were accompanied by a band sponsored by the
Goodyear Tire & Rubber Company,
which no doubt saw an opportunity
to promote land travel and transportation in peace time as well as war.
The convoy of 81 vehicles, which
was seen off from Washington on July 7
with speeches from the Secretary of War
and numerous senators, took 62 days to
cover 3,250 miles through Maryland,
Pennsylvania, Ohio, Indiana, Illinois,
Iowa, Nebraska, Wyoming, Utah, Nevada and, finally, California. There were
naturally crowds of well-wishers along
the way, and there were speeches and
festivities befitting the arrival of such
a parade of equipment in the towns
it passed through. Perhaps not to be
outdone by Goodyear, the tire magnate
Harvey Firestone welcomed the traveling army to his estate in Akron, where
“a covey of young ladies dressed in gay
frocks treated the men with a magnificent feast.”
Gaiety and politicking may have
slowed somewhat the progress of the
convoy, but it nevertheless did set what
was, for the time and circumstances, the
remarkable pace of 58 miles per day, or
about five miles per hour—not much
Henry Petroski is Aleksandar S. Vesic Professor
of Civil Engineering and a professor of history at
Duke University. Address: Box 90287, Durham,
NC 27708-0287
396
The Interstate
Highway System
turns 50 this year
faster than a brisk walk. Although excruciatingly slow by today’s standards,
it was the best that the caravan could
do at the time. The journey had to be
undertaken in the heat of summer to
ensure that the western mountains
were passable. The season, however,
also meant that what roads there were
would be muddy after rain. Vehicles
would overheat and otherwise break
down. There were accidents to deal
with. Roads, where they existed, were
often so rough that no significant speed
could be achieved. Even the better
roads were frequently interrupted by
rivers, which were often crossed by ferry. If there was a bridge, it was often too
light for military vehicles to use without breaking it. Thus, it did not take a
great leap of the imagination for Lt. Col.
Eisenhower to conclude that the United
States would benefit greatly from an
improved system of highways. His feelings on the matter would intensify during World War II, when he witnessed
firsthand the great advantages of the
German Autobahn. All these experiences would inform Eisenhower’s policy
making when he became president.
Named Routes
Although it may have been encumbered by heavy equipment and hoopla,
the army convoy that so negatively impressed Eisenhower was far from the
first transcontinental driving experience. In 1903, Horatio Nelson Jackson
drove with his personal mechanic from
San Francisco to New York, paving the
way on ways that were not paved, in 63
days. The first woman to drive across
the country was Alice Huyler Ramsey,
who with three other women in her
green Maxwell made it from New York
to San Francisco in only 41 days in 1909.
The idea for a transcontinental road,
as opposed to a transcontinental trip,
was put forward in 1913 by Carl Graham Fisher, builder of a motor speedway on the outskirts of Indianapolis.
Fisher argued at the time that America’s highways were “built chiefly of
politics,” when the “proper material is
crushed rock or concrete.” He proposed
a “coast-to-coast rock highway” that
would run from Times Square in New
York to Golden Gate Park in San Francisco, and he hoped that it might be
completed in time for the opening of
the Panama-Pacific Exposition in 1915.
Fisher proposed that the rock highway be funded by “automobile barons” like Henry Ford, but Ford opposed the idea, arguing that if private
industry began to pay for good roads
the government would never be expected to do so. Henry Joy, president
of the Packard Motor Car Company
and one of the supporters of Fisher’s
idea, suggested that the road be named
the Lincoln Highway and be dedicated to the revered president. In this
way, the federal government might be
persuaded to divert to the highway
project the $1.7 million intended for
a marble memorial to be erected in
Washington. That did not occur, but
with the Federal-Aid Road Act of 1916,
funds began to be made available to
the states—but not directly to private
roads—on a matching basis.
According to the Wannamaker Diary for 1917, 13 transcontinental highway “through routes” were then being
planned—about evenly divided between
east-west and north-south routes—but
they were only “in the first stages of permanent improvement.” In addition to
the Lincoln Highway, east-west routes
included the Pike’s Peak Ocean to Ocean
American Scientist, Volume Copyright © 2006 by Henry Petroski. Requests for permission to reprint or
reproduce this article should be directed to the author at [email protected].
Dwight D. Eisenhower Presidential Library
Dwight D. Eisenhower Presidential Library
Lieutenant Colonel Dwight D. Eisenhower
(above, right)—shown here with Major Brett
(left) and Harvey Firestone (middle)—participated in a 1919 transcontinental military convoy. The journey took 62 days and entailed
considerable hardship (right). The experience—along with seeing the German Autobahn during World War II—would inform
Eisenhower’s decision, more than 35 years
later, to push for the construction of the U.S.
Interstate Highway System.
Highway (New York to California), the
National Old Trails (Washington, D.C.,
area to Los Angeles), Trail to the Sunset and Santa Fe Trail (New York to San
Diego), and the Old Spanish Trail (St.
Augustine to San Diego). North-south
routes included the Atlantic Highway
(Calais, Maine, to Miami), Pacific Highway (Vancouver to San Diego), the Dixie Highway (Chicago to Miami) and
the Jefferson Highway (New Orleans to
Minneapolis-St. Paul). A “diagonal automobile road across the country” was
also in the planning stages. It was to be
the longest on the continent and was to
be given the pedestrian name of Savannah to Seattle Highway. At the time such
plans were being put forth, there were
3.5 million automobiles and a quarter
million trucks waiting to use them, but
these numbers were dwarfed by a national population of 21 million horses.
By 1925, there were numerous named
roads throughout the country. Individual states developed segments of these
routes that maximized travel within
state boundaries, thereby increasing
the local and regional benefits of tourist dollars. Utah, for example, rather
than completing a section of the Lincoln
Highway spent its highway money on
the Arrowhead Route to Los Angeles.
Also, it developed the Wendover Road
as an alternative to the Lincoln Highway for travelers on their way to San
Francisco. The named-highway system
was becoming increasingly cumbersome to master and confusing to use.
Even intrastate routes were difficult
to master outside one’s familiar area,
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and solutions had been sought. By 1917,
the New York State Highway Commission introduced a color code for identifying main routes throughout the state.
Bands of color on telegraph and telephone poles and other stationary objects, like bridges, distinguished classes
of routes: Red indicated a principal
east-west route, blue a north-south, and
yellow a diagonal route. In so marking
its roads, New York joined Massachusetts, Connecticut, Rhode Island and
New Hampshire in the practice, thereby making regional driving and touring
more easily accomplished. At the same
time, Wisconsin began replacing named
trail and highway signs, which often
consisted of little more than a distinctive color band painted on a telephone
pole, with numbered route markers of a
distinctive shape.
Take a Number
In 1925, the American Association of
State Highway Officials began to rationalize the system of roads and road
signs across the nation. Henceforth, U.S.
highways—a designation that was not
meant to suggest that they were federal
highways (for they were not) but rather
that they were major routes through
large stretches of the country—were to
be known primarily by numbers, not
by the colorful names that often had
little intrinsic direction or location informational content. The scheme introduced by AASHO (now known as
AASHTO and pronounced “ash-toe”
because transportation officials are also
included in the rubric) designated ma-
jor east-west routes with numbers that
are multiples of ten, with U.S. 10 being
the most northerly route and U.S. 90
the most southerly. Major north-south
routes, of which there were expected to
be many more than east-west, were to
have numbers ending in a 1 or a 5. Thus
it was the location and direction of U.S.
1 that gave it that designation—and
not, as is commonly stated, that it was
the first national highway. By AASHO’s
ordering principle, U.S. 1 ran along the
east coast between Maine and Florida;
U.S. 101 was the west-coast highway
between California and Washington.
Under this scheme, the Lincoln Highway lost its identity as a single route,
different sections of it carrying different
numbered designations, but devotees
installed thousands of roadside markers identifying it as the highway dedicated to Abraham Lincoln.
President Franklin Delano Roosevelt
had a direct and personal interest in the
condition of America’s roads. He was
an ardent automobile driver, and when
paralysis in his legs restricted his ability
to drive, he designed a system of levers by which he could control the pedals with his hands and thereby enjoy
driving himself around the countryside
near Warm Springs, Georgia, where he
had gone for hydrotherapy. Roosevelt’s
love of the road was exhibited in a 1936
memorandum in which he reiterated a
route of his own design connecting the
Shenandoah National Park in Virginia
to Worcester, Massachusetts. The following year, he called the chief of the
Bureau of Public Roads to the White
Copyright © 2006 by Henry Petroski. Requests for permission to reprint or
reproduce this article should be directed to the author at [email protected].
2006 September–October
397
Brian Hayes
vention, First Lady Mamie Eisenhower
hosted a White House reception for car
dealers’ wives and “was dazzled by the
furs and diamonds the women wore,”
attesting to the prosperity of the industry. There were more than 60 million motor vehicles registered in America at the
time, and the number was continuing
to grow. New roads were sorely needed.
Before the development of route numbers,
roads were named and often had markers—
here one for the National Highway in Ohio.
House to show him a map of the U.S.
on which Roosevelt had inscribed three
north-south and three east-west that he
envisioned as a system of transcontinental toll routes. The idea did not catch
on at the time, but it would be revised
with gusto in the postwar period.
Dwight Eisenhower assumed the
presidency in 1953, bringing to office
his negative early experience with
cross-country driving. His appointees
soon put forth proposals to develop in
earnest a true interstate highway system. One proposal from his administration was to form a National Highway
Authority (NHA) that would abolish
state highway departments. Among
the obstacles to realizing such a scheme
was the fact that the federal government had no authority under the Constitution to build or maintain any roads
at all. Ideas for financing any system of
interstate roads ranged from all costs
being borne by the states to complete
federal funding. Eisenhower himself,
being a fiscal conservative, at one time
favored a system of toll roads that
would be self-liquidating—that is, the
tolls would last as long as it took to pay
off the debt incurred to construct the
highways. In the end, compromises of
all kinds had to be made.
Meanwhile, automobiles continued to
multiply. In the mid-1950s, a president of
the National Automobile Dealers Association could declare, “We have not built
as many miles of highway since World
War II as we have built miles of passenger cars.” When the association met
in Washington, D.C., for an annual con398
Lake City, was finally opened in 1986,
but still only 97 percent of the system
that would eventually total over 46,000
miles of roadway was completed at that
time. Much of it, built to 1972 standards
and traffic expectations, was already
obsolete and in need of constant widening and upgrading, as interstate travelers are all too well aware.
The Interstate System Is Born
More Number Games
After a couple of years of intense debate, the Federal-Aid Highway Act of
1956 was finally passed, thus providing
the basis for calling 2006 the 50th anniversary of the Interstate System. Among
the enticements that finally won over
sufficient support for the legislation
was the promised miles of interstate
highways around cities, where voters
and hence their representatives’ votes in
Congress were concentrated. President
Eisenhower signed the bill without ceremony—he was in Walter Reed Army
Medical Center at the time, recovering
from ileitis surgery. Since he was looking forward to being nominated for a
second term, he did not want to appear
in public in a weakened state. In the bill
that Eisenhower signed, almost 37 years
to the day since he had set out from
Washington with the convoy headed
for San Francisco, $25 billion was authorized over 12 years for constructing
a National System of Interstate and Defense Highways. It increased the federal
gas tax to feed a Highway Trust Fund,
put the federal share of interstate construction costs at 90 percent, expedited
the process of acquiring rights-of-way,
established standards for such physical
features as lane and median width, and
set a completion date of 1972.
Massachusetts Route 128 around Boston, with its limited access and remote
location from the congested city center,
served as a model for much of the Interstate System. When it first opened in
1951, Route 128 was referred to as “the
road to nowhere,” but by the time serious planning for the interstates began,
the economic development that Route
128 had attracted, especially around its
exits, was undeniable. The promise of
the Interstate System was not fully realized by the legislative deadline of 1972,
however, for there arose opposition to it
from groups ranging from environmentalists to neighborhood preservationists. Indeed, the first fully completed
transcontinental interstate highway was
I-80, which runs from New York to San
Francisco. Its final section, through Salt
Among the less technical but still very
important challenges to making the Interstate System user-friendly was establishing a clear and distinctive system
of signage that was readily readable
and understandable to a driver going
along at Interstate speeds. The numbering system adopted mirrored that
of the U.S. highways. Major east-west
interstate routes were given numbers
that were multiples of 10, but with the
lowest numbered (I-10) being the most
southerly and the highest (I-90) the
most northerly. This scheme thus minimized the occurrence of nearby U.S.
and Interstate System routes carrying
the same number. Major north-south
Interstate routes end in a 1 or 5, but
with the lowest number (I-5) running
along the West Coast and the highest
(I-95) along the east. Lesser interstates
were to be given even or odd numbers
according to whether their predominant direction was east-west or northsouth, respectively.
Triple digits are used to designate
interstate spurs or beltways that branch
off or connect to the main interstate
routes. Thus, I-495 is the Capital Beltway around Washington, D.C., which
allows I-95 thru traffic to avoid the
congestion of the central city. There is
also an I-495 beltway around Boston,
but there is little chance of confusion
between identically numbered routes
almost 500 miles apart. Baltimore, however, is less than 50 miles from Washington, so designating its beltway I-495
could have been confusing. Thus, Baltimore’s is designated I-695. The spurs
I-295 and I-395 both lead into the heart
of Washington from I-95 and its associated beltway. There are also interstate
spurs designated I-595 and I-895 in the
Washington-Baltimore area, the former
connecting the Washington beltway
with Annapolis and the latter providing an alternative tunnel route under
Baltimore Harbor.
Establishing a rational numbering
system solves only part of the problem
of designating highway routes. To be
American Scientist, Volume Copyright © 2006 by Henry Petroski. Requests for permission to reprint or
reproduce this article should be directed to the author at [email protected].
truly useful, the numbers must be effectively displayed on distinctive signs.
It was clearly important to distinguish
the interstates from the U.S. routes, especially in the Midwest where the numbers of nearby roads might be close if
not identical. The route signs for the
U.S. highways have since 1926 carried
black numbers on a “U.S. shield” with a
white background. After the interstate
highway act was signed into law, the
state highway departments were invited to propose designs for route signs.
Most of the states submitted concepts
that incorporated the name of the state
through which the Interstate would
pass, and the now-familiar red, white
and blue “federal shield” design represents a combination of the ideas submitted by Missouri and Texas—employing
the top half of one design and the bottom half of the other.
Signs Shape Up
Of course, roads and highways also
need signs to warn, control and direct
traffic. The value of distinctive sign
shapes for conveying different kinds of
information and instruction dates from
at least 1922, when a group of Midwestern state highway officials sought
to standardize markings for drivers
traveling among their states. They
pointed out that the shape of a sign
could convey considerable information
even in the dark. Their first proposal
was for black-and-white signs, but this
was soon changed to black printing on
a light background (“preferably lemon
yellow”) by an AASHO sign committee. To further distinguish the octagonal STOP sign, it was recommended
that it have a red background, but
finding a sufficiently durable red paint
proved difficult, so a black-on-yellow
scheme was adopted at the time.
The problem of choosing a color
scheme for signage arose again in the
mid-1950s when distinctive standards
for interstate highway exit signs were
being developed. It was agreed that
they should be readable at 800 feet,
but the color scheme became a subject
of some debate. White printing on a
green background was recommended
by an AASHO committee working in
conjunction with the Bureau of Public
Roads, but the newly selected federal
highway administrator, Bertram Tallamy—who was actually color blind—insisted that a dark-blue background, as
used on the New York State Thruway
with which he had been affiliated, was
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a superior choice. The committee representing the states was equally insistent
that green was better. In the end, the
issue was resolved by constructing a
roadway section on which were erected
differently colored signs directing drivers to “Metropolis” and “Utopia.” Motorists who drove at 65 miles per hour
past the signs to make-believe destinations were polled on background color
preferences. At 58 percent, green was
the overwhelming choice over blue (27
percent) and black (15 percent). Now,
of course, the familiar white-on-green
signs are emblematic of the interstates.
The readability of highway signs has
long been of interest to transportation
engineers, and the ubiquitous typeface
so familiar to drivers for decades was
dictated in the Federal Highway Administration Standard Alphabets for
Traffic Control Devices. However, as
the population was aging it became increasingly obvious that there was going
to be a growing percentage of drivers
over 65 on the roads and that the vision
of these drivers could be expected to
decline as they aged. Among the problems known to afflict such a population
of motorists was difficulty in distinguishing some letters, especially under
nighttime driving conditions. An early
proposal was to increase the font size
used on highway signs by about 20 percent. A larger type size would naturally
require a larger sign area, which would
have meant not only more-costly signs
but also more “visual clutter” on the
roadscape.
In the late 1980s, Donald Meeker, a
sign designer originally hired by Oregon for a project, teamed up with
James Montalbano, a type designer,
to improve the legibility of highway
signs. They ended up modernizing and
rationalizing the FHA’s alphabets that
dated from mid-century, and which
they claimed “had never really been
tested.” The pair of designers focused
on such details as redrawing the vowels
a, e, and u, which “tend to ‘fill in’ under
bright lights, making them indistinguishable,” and the vowel i, which can
sometimes look like an l. The visibility
of signs employing the new typeface
of Meeker and Montalbano was compared with that of signs using the old
one by erecting examples of each on
a test track, and the redesigned letters
remained sharp from distances as much
as 50 percent farther. The new typeface
was christened Clearview; in 2004 it
was granted interim approval by the
The original Gothic typeface used on Interstate signs (top) is now being superseded by
the new Clearview typeface (bottom), which
is legible at 50 percent greater distance.
FHA, and examples of the signs were
erected on sections of I-80 and I-380 in
Pennsylvania. The improved legibility
was estimated to reduce reaction time
by as much as two seconds, which can
give a significant advantage to a driver
traveling at interstate speeds.
American highways and their accessories have improved dramatically
since Lt. Col. Eisenhower traveled in an
army convoy across the nation. Where
he found rocky roads, mud and unbridged rivers and streams, today’s Interstate System drivers expect to ride
on a smooth, hard road surface and
hardly notice the streams and rivers
over which they are carried by bridges
they may not even realize are beneath
them. The uniformly marked lanes and
shoulders give visual and auditory cues
to which we react without hardly thinking, and the standardized road and exit
signs help us negotiate even the most
unfamiliar highway territory. And for
those teams of drivers who can tolerate
all the sameness of the Interstate System, especially at night, the drive from
Washington to San Francisco might be
accomplished in as few as a couple of
days. We and the roads on which we
drive have come a long way.
Bibliography
American Association of State Highway
and Transportation Officials. 2006. Interstate 50th Anniversary. http://www.
interstate50th.org.
Hayes, Brian. 2005. Infrastructure: A Field Guide to
the Industrial Landscape. New York: Norton.
Lewis, Tom. 1997. Divided Highways: Building
the Interstate Highways, Transforming American Life. New York: Viking.
Lin, James. 1998. Lincoln Highway. http://
www.ugcs.caltech.edu/~jlin/lincoln/
history/part4.html
Patton, Phil. 2005. Road signs of the times. New
York Times, January 21, D8.
Reid, Robert L., Laurie A. Shuster and Jay
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Copyright © 2006 by Henry Petroski. Requests for permission to reprint or
reproduce this article should be directed to the author at [email protected].
2006 September–October
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