Civil Engineering Reference
In-Depth Information
Table 6.5 Spatial trends, urban population, 1940
-
2000
Year
Central city
metro
population ratio
Average metro density
(persons per square
mile)
Density gradient
-
Ratio
Change
Density
Change
Gradient
Change
1940
0.61
8,654
0.72
−
−
−
−
1950
0.57
0.04
8,794
140
0.64
0.08
−
−
−
1960
0.50
−
0.07
7,567
−
1,227
−
0.50
−
0.14
1970
0.46
0.04
6,661
906
0.42
0.08
−
−
−
−
1980
0.42
0.04
6,111
550
0.37
0.05
−
−
−
−
1990
0.40
−
0.02
5,572
−
539
−
0.34
−
0.03
2000
0.38
−
0.02
5,581
9
−
0.32
−
0.02
Source
Reference [
5
], p. 39, Table 2-1. Copyright
National Academy of Sciences, Washington,
DC, 2009. Reproduced with permission of the Transportation Research Board
©
Table 6.6 Employment trends inside and outside the central city, 1980
1990
-
Northeast
Midwest
South West
Buff NYC
Phil
Chic
Clev Detr
Hous
Denv
LA
Port
SF
Sea
Percent change
Total employment
13.2
26.7
28.6
20.3
9.1
19.1
34.9
30.9
48.8
34.8
42.1
48.8
Central city
1.2
22.2
7.7
13.3
−
4.0
−
6.9
22.4
4.0
32.7
23.8
23.3
21.8
Not central city
21.0
30.5
37.2
25.3
14.7
29.2
61.3
56.2
58.4
43.4
46.8
66.5
Central city share (%)
1980 39 46 29 41 30 28 68 49 37 44 20 39
1990 35 45 25 39 26 22 62 39 33 41 17 32
Note Buff
Buffalo;
NYC
New York City;
Phil
Philadelphia;
Chic
Chicago;
Clev
Cleveland;
Detr
Detroit;
Hous
Houston;
Denv
Denver;
LA
Los Angeles;
Port
Portland;
SF
San Francisco;
Sea
Seattle
Source
Reference [
5
], p. 44, Table 2-2. Copyright
©
National Academy of Sciences, Washington, DC, 2009.
Reproduced with permission of the Transportation Research Board
6.2.3 Factors Contributing to the Rate of VMT Growth
The large change in the annual VMT growth rate from 3,700 in 1956 to 9,564 in
2008, corresponded to a signi
cant increase in the labor force participation rate, an
expansion of population growth in suburban areas and an increase in private vehicle
ownership at twice the rate of population growth. Table
6.7
summarizes some key
trends [
7
]:
an increase in the number of workers in the population
—
from 36.1 % in 1960,
'
—
to 45.6 % in 2000 due largely to women
s increase
whose daily trip rates are
22 % greater than the daily trip rate of non-workers;
a doubling of per capita motor vehicles ownership from 0.31 in 1960 to 0.63 in
2000 with an equivalent increase in daily vehicle trips per capita.
