Civil Engineering Reference
In-Depth Information
Table 6.9 Daily person trips per person, by vehicle ownership status of household and size of
metropolitan area (2001)
Size of metro area
Households with vehicles
Households without vehicles
<250,000
4.45
2.51
250,000
499,999
4.21
2.56
-
500,000
999,999
4.28
2.69
-
1
-
2.9 million
4.24
2.57
3 million+
4.07
2.93
Source
Reference [
9
], Table 33
—
2001 NHTS summary of travel needs
6.2.3.3 Persons in Households with Autos Generate More Travel
Households have increased their car ownership over time ([
3
], p. 39, Fig. 2.36). the
increases in vehicle ownership has increased travel demand across all metropolitan
areas (Table
6.9
), with vehicle owning households members traveling signi
cantly
more than those living in households without vehicles.
6.2.3.4 Trips by Persons in Higher Income Households Are Longer
Travel demand increases with household income. Table
6.10
shows that the average
trip length increases with income
more so for income increments at the lower end
of the income scale and reaching a plateau at higher income increments.
As the US personal incomes rise, the value of travel time increases and travelers
switch from lower to higher speed modes: from walking
—
to
private vehicle. As shown in Table
6.11
, the greater mobility provided by the
private vehicle has increased the average distance traveled for every age group.
Over this 18-year interval, increasing personal income, smaller household size,
and greater ownership of private vehicles, contributed to increasing traveler
mobility by an average of 0.82 daily miles per year. This per capita increase,
however, was not uniform across all age groups and during the 18-year interval. As
shown in Table
6.12
, it varied from an average of 1.4 daily miles per year from
1983 to 1990. It was followed by an average increase of 0.76 miles per year from
—
to biking
—
to bus
—
Table 6.10 Average trip length in private vehicles versus all modes
Household income
Using private vehicles (miles)
Using all modes (miles)
Less than 20,000
6.7
5.6
20,000
39,999
7.4
6.7
-
40,000
-
74,999
7.7
7.1
99,999
7.7 7.1
100,000 and over 7.7 7.1
All households 7.5 6.8
Source
Reference [
11
], Table 11, p. 64, and calculated by the authors from Reference [
10
]
75,000
-
