Civil Engineering Reference
In-Depth Information
Table 6.3 Land use and travel indicators
—
central cities versus suburbs
Indicators
Central cities
Suburbs
Separation of land
use activities
Activities located close
together
Activities located far apart
Trip length
Shorter
Longer
Car ownership and
use
Lower per capita car
ownership and use
Higher per capita car ownership and
use
Transit availability
and use
Higher transit quality and
higher use
Transit not available or of poor
quality and lower use
Modal alternatives to
the car
Many
None to few
Traffic speed
Lower
Higher
Table 6.4 Population growth versus land area growth in selected metropolitan area, 1970
1990
-
Urban region Population change (%) Land area change (%)
Chicago 4 46
Los Angeles 45 300
New York City 8 65
Seattle 38 87
Source
References [
4
], Table 15-50, p. 15-106 and [
14
]. Copyright
©
1996 Island Press.
Reproduced by permission of Island Press, Washington, DC
6.2.1.1 Dispersion of Population and Employment
The dispersion of population and employment increases vehicle travel. Tables
6.5
and
6.6
, extracted from Transportation Research Board Special Report 298,
“
Driving and the Built Environment
”
illustrate those trends [
5
].
Table
6.5
shows that while the proportion of people living in the central city has
consistently declined from 0.61 in 1940 to 0.38 in 2000, the average metro area
density declined from 8,454 to 5,581 people per square mile.
Table
6.6
gives employment trends inside and outside the Central City for
11 metropolitan areas. This shows that between 1980 and 1990 the central city
share declined in all 11 areas while the suburban share increased.
6.2.2 Per Capita VMT Growth
In 2008 the average person contributed an annual average of 9,564 vehicle-miles of
travel (VMT) on US roads. This grew from an annual average of about 3,700
vehicle-miles in 1956. By 1998 the VMT per capita reached its peak value of 9,603
vehicle miles, staying within this range until 2005 and beginning to drop slightly to
a value of 9,564 in 2008 [
6
].
