Civil Engineering Reference
In-Depth Information
2.2.1 Ancient Time
Ancient cities were compact places with buildings located close to one another and
connected by narrow streets. Most people lived within a 15 min walk of their work
places, and their streets were predominantly used for pedestrian movement as well
as for many commercial and social activities.
Population Densities [
1
]
Examples of ancient population densities are:
(1) Babylon and Rome with peak populations of over
million, were contained
within an area of 14 Km
2
. or less, and had an effective radius under 2 km.
(2) The population of Baghdad in about 900 AD, was 900,000
½
the largest that
could be practically accommodated within a walking city. Its population
density peaking at 600 persons per hectare (243 per acre, or 155,500 persons
per square mile).
—
Julius Caesar found it
necessary to issue an order prohibiting the passage of wagons through the central
district for 10 h after sunset
Ancient cities suffered from street congestion. In Rome,
'
'
[
1
]
—
a more stringent regulation than is found in any
modern city.
Mobility in medieval cities
was provided
by walking on narrow and crooked lanes/alleys unsuitable for wheeled traf
—
hemmed in by their defensive walls
—
c.
2.2.2 The Industrial Revolution (ca. 1825
-
1900)
In the years of the Industrial Revolution, land development in cities continued to
locate around the walking mode. During this period cities had high population
density; streets were narrow, congested, and often polluted with horse manure and
dead animals.
The growth of cities around the beginning of the 20th century was made possible
by the steel-framed building construction that allowed taller buildings at the city
center, and by electric traction that provided speeds of 8
12 miles per hour. At the
same time, mechanization of agriculture enabled many people on the farms to
migrate to the cities
-
a trend that continued through the 20th century.
The rise and spread of cities has paralleled the growth and speed of transpor-
tation. Improved transportation has played a crucial role in the transition from a
rural to and urban society.
People looking for employment and a more promising economic future migrated
from the countryside to the industrial city contributing to its extremely crowded
living and travel conditions. By 1900,
—
population densities in London and Paris
peaked at over 700 people/ha. (283 per acre, or 181,000 per square mile), and in
New York City they reached 1,350/ha
“
”
(546 per acre, or 350,000 per square mile in
