Civil Engineering Reference
In-Depth Information
Table 6.14 Trends in
demographics and private
vehicle travel, indexed to
1969 (1969 = 1.00)
1969
1977
1983
1990
1995
2001
Population
1.00
1.08
1.16
1.21
1.32
1.41
Households
1.00
1.21
1.37
1.49
1.58
1.72
Workers
1.00
1.23
1.36
1.56
1.73
1.92
Drivers
1.00
1.24
1.43
1.58
1.71
1.85
Household
Vehicles
1.00
1.66
1.98
2.28
2.43
2.79
Household
VMT
1.00
1,17
1.29
2.18
2.67
2.93
Source
Reference [
9
]
6.2.4 Trends in VMT and Contributing Factors
From 1969 to 2001, the household VMT more than doubled (2.93/1.41) the growth
in population (Table
6.14
). The impact on VMT of suburban population growth was
magni
ed by the growth rate in the number of households, workers, drivers, and
privately owned vehicles.
6.3 The Plateau Effect of Factors Inducing VMT Growth
The preceding discussion indicated a VMT growth over the last half century that
has closely reflected the pattern of growth in its causative factors (population,
income, auto ownership, workers, increasing suburbanization of metropolitan
areas). It has increased proportionately with the growth of these variables, and it has
slowed down when the growth of these variables slowed.
The annual VMT
growth rate
was 5.2 % in the 1969
1990 period, and has
decreased to less than 1 % per year since 2004, reaching a negative growth in 2006
-
-
2007 (Table
6.15
). The last time of a VMT negative growth was in 1980 [
7
].
Table 6.15 Changes in VMT
(1969
Period
Growth
in period (%)
Average annual
rate (%)
2007)
-
1969
1990
+110
+5.2
-
1990
2001
+31
+2.8
-
2004
-
2005
+0.8
+0.8
2005
-
2006
+0.6
+0.6
0.3
Source
Reference [
7
], calculated from Fig. 1a
2006
2007
0.3
-
−
−
