Environmental Engineering Reference
In-Depth Information
CHAPTER
8
Transportation
8.1
INTRODUCTION
Near the end of the nineteenth century in the United States, a predominantly steam powered, coal-
fueled transportation system had aided the transformation of what had been a mostly agricultural
economy at the century's beginning into one dominated by industrial activity. Railroads, coastal
ships, and river barges moved farm produce and forest products to urban consumers, mineral ores
to refineries and steel mills, and coal to industrial, commercial and residential consumers. Except
for the affluent who could afford horse-drawn carriages, most urban and rural workers walked from
home to the place of employment. In the major cities, however, horse-drawn or electric-powered
streetcars provided passenger transport for daily travel where residential areas spread beyond
the urban core in response to population growth. Long-distance passenger travel was exclusively
provided by trains and ships. Nevertheless, horse-drawn wagons were necessary for the distribution
of food and goods within urban and rural regions alike, and animal power provided the source of
much agricultural energy.
The development of the internal combustion engine (ICE) and its supply of liquid fossil
fuel transformed both urban and rural communities in the twentieth century, most markedly by
greatly expanding the kind and function of transportation and work vehicles. By the century's
end, practically all adults had the use of an automobile for commuting to work or other personal
daily travel. Passenger travel to and in central urban areas by bus and electric-powered rail (above
ground, at ground level, or underground) complemented the need for personal travel where the
density of travel could not be accommodated by automobiles alone. Most freight moved by truck,
but bulk commodities were shipped by rail and river barge. The rapid development of commercial air
travel, beginning at midcentury, expanded long-distance travel availability, superseding railroads,
which had already lost market share to intercity buses and private automobiles. ICE powered
tractors revolutionized agriculture, and rural farm population declined drastically. Work machines
(bulldozer, chain saw, construction crane, etc.) greatly increased human productivity in tasks that
previously consumed large amounts of hard human labor.
The growth of transportation in the twentieth century paralleled that of electric power, with
both becoming major factors in the economies of developed nations at the century's end. In the
United States in 1996, transportation and electricity accounted for about 25% and 45% of the total
primary energy consumption, respectively. The availability of both electric power and transportation
in modern industrial societies is an important factor in human productivity, although the efficiency
of their use may well be improvable.
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