Civil Engineering Reference
In-Depth Information
However, just as city streets before the car era were crowded and congested, the
popularity of the suburbs has attracted many people and jobs over time creating
traf
c congestion on many freeways and arterial roadways.
Understanding how transportation technology in
uences the character of land
development is fundamental to establishing policies aimed at sustaining desirable
levels of mobility and accessibility in light of increasing travel growth and traf
fl
c
congestion. Addressing these concerns is a major challenge especially in the US
where the zoning of land use is typically controlled by local governments whose
decisions are often made separately from decisions that States make about major
transportation investments.
This chapter sets forth some key issues that should be considered when for-
mulating policies and programs addressing urban and suburban traf
c congestion,
and it shows that traf
c congestion has usually followed urban development.
2.2 Transportation Technology, Urbanization, and Travel
The predominant type of transportation available at a particular time in history
(non-motorized,
fixed route transit, or motor vehicles) has in
fl
uenced the location
and density of residential and non-residential activities.
Transportation and land use are two interconnected elements of the urban system
and structure. The locations of activities re
ect the daily need for access to jobs,
shopping, educational or social needs of the population. Access to these people-
oriented activities is determined by the prevailing transportation technology, and by
the time people budget for travel.
Traveler and goods mobility was provided by walking and animal power for
thousands of years until the dawn of the industrial revolution.
Land travel was by foot (2
fl
3 mph) or by the use of animal power (horse speed of
-
4
6 mph). At these travel speeds the distance one could cover within acceptable
travel times was very short and for this reason land use activities were located close
together.
With the introduction of mechanized travel, speeds increased substantially
allowing people to travel farther within the same travel time budgets. This increased
mobility encouraged the separation of various activities, expanded the amount of
urbanized land, and reduced population density in central areas.
The transition from high density urban developments to lower density ones is
closely related to the transportation technology prevailing at various times in
history.
Lay [
1
] in his remarkable topic
-
“
”
The Ways of the World
provides many
examples of how transportation technology in
uenced the character of cities and
urban development. Salient highlights are as follows.
fl
