CHAPTER - 2 URBAN STRUCTURE 2.1 Urban Activity

CHAPTER - 2
URBAN STRUCTURE
2.1 Urban Activity System
Many observers of urban areas have pointed out that bulk of urban activities occurs in
ordered hierarchies. Certain activities, such as elementary schools and small neighborhood
shopping centers, exist at a scale that serves only local areas. Other type of urban activities exists
in large concentrations and may serve an entire urban region. Examples of region wide activities
include major cultural facilities, Post secondary education facilities, specialized retail trade
outlets, and certain types of personal service.
tto
Figure: 2.1 Weekly household activity Patttern
ure 2.1 show
ws the weeekly activity
y pattern forr the membbers of one household. This
Figu
diagram indicates ap
pproximately
y the length and locatioon of each trrip, the modde of travel used,
and the number
n
of triips made thrroughout the week.
Figuree 2.2: Hierarchical stru
ucture of hou
usehold – b
based activitties
Figu
ure 2.2 illusstrates an idealization of the hierarcchy of somee of the acttivities locatted in
urban arreas. Two activity systeems are identified in fi
figure 2.2 annd these aree the houseeholdworkplacce subsystem
m and the ho
ousehold serrvice place ssub system. Service plaaces are of a very
general nature and include scchool, perso
onal servicees, and cerrtain types of culturall and
ment facilitiees. The activiities labeled as ‘non-houusehold-servving employm
ment’ areenvironm
(1) Employment
E
in basic indu
ustries
(2) Employment
E
in populatio
on serving in
ndustries
The
T regional center migh
ht contain go
overnment ooffices speciaalized retail trade outletts and
personal service as well
w as the major
m
culturall facility of tthe region
NB:
N - Home--based traveel demand reepresents 800% of the tootal travel inn urban areaas. In
addition, travel by co
ommercial vehicles in no
ormally 12 too 15% of tottal vehicle trrips with in uurban
areas.
2.2 Urba
an Movemen
nt Hierarch
hies:
Transport
T
Sysstems Provid
de two fundaamental funcctions and thhese movem
ment and acceess to
land baseed activities. There is a conflict
c
betw
ween these tw
wo functionss.
Avg.
d
Speed
(mph))
Figu
ure 2.3: Top
p speed of veehicle (mph
h)
t Vehicle Speed, Statiion Spacing and Stationn Stop
Average Speed of traavel by mass transit vs top
Time.
hows that th
he station spaacing on rappid transit liines controllling factor iin the
Figure 2.3 sh
s
of trav
vel on these lines. In oth
her words, ass access to a rapid transitt line is increeased
average speed
through decreased sttation spacin
ng, the efficciency of moovement deccreases. A S
Similar effecct for
road trav
vel has been illustrated that
t
the efficciency of traavel along ccontrolled acccess roads is far
superior to travel alo
ong arterial and collecttor roads wiithout controol of access, or with lim
mited
control of
o access.
Figure 2.4
2 Hierarch
hical Classiffication of rroad types.
Figure 2.4 illlustrates onee hierarchical Classificaation of roaads which consists of
w the follo
owing Properrties.
classes with
four

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