Civil Engineering Reference
In-Depth Information
Table 5.2 CBD employment trends
Year
Ratio
CBD
Area
(square miles)
1980
1990
2000
2000/1980
Chicago, IL, CBD
1.15
353,984
325,226
341,014
0.96
Chicago, IL, Expanded
CBD
3.55
503,109
503,787
523,382
1.04
Philadelphia, PA
2.4
265,135
287,860
265,838
1.00
San Francisco, CA
2.55
314,100
312,100
341,100
1.09
Oakland, CA
1.72
49,400
54,400
63,100
1.28
San Jose, CA
3.17
44,300
39,000
52,400
1.18
Source
Reference [
2
], p 440, Table
12.2
commercial centers made them grow in size and many became the precursors to the
mega-centers of multiuse activities [
3
].
Examples of reported travel modes are shown in Table
5.3
. In contrast to the
central business district, outlying activity centers rely largely on automobile access.
More than 90 % of the suburban centers destinations are by automobile (except
for Nassau Co., New York). Accordingly, the concentration of commercial and
retail activities located along major arterial roads, and at the nodes of major arterial
roads and freeways has created excessive concentration of traf
c at many locations
that far exceeds roadway capacity causing severe congestion for many hours of the
day [
3
].
Because population density of many suburban areas is too low to support
effective transit service, it is not generally possible to substantially reduce traf
c
congestion by providing transit access to many mega-centers. And even where
Table 5.3 Travel modes in suburban centers
Location
Year Drive
alone (%)
Car
pool (%)
Total auto
user (%)
Transit
(%)
Other
(%)
Nassau (NY)
1987
79
8
87
13
-
Bellevue (WA)
2000
82
8
90
8
2
Shady grove (MD)
1992
90
6
96
3
1
South coast plaza (CA)
1998
75
20
95
3
2
Parkway center
(Galleria) (TX)
1988
90
5
95
1
-
Perimeter center (GA)
1988
94
5
99
1
-
Tysons corner (VA)
1988
89
10
99
1
-
South dale (MN)
1988
92
7
99
1
-
Overall average
(rounded)
86
9
95
4
1
Source
Reference [
3
], p 457, Table
12.11
