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APPENDIX SIX
Functional Classification of Roadways
The Transportation Plan Map designates the arterial roadway system required
to meet the programmed development plan. Design standards are provided for all
functional classifications of roadways. It is necessary, therefore, to understand the
purpose of each functional roadway type in order to better understand the need for
varying right -of -way widths, spacing standards, speed limits, and other design
criteria. This section provides that explanation.
Some roadways are intended to provide access to the thoroughfare system from
adjacent land uses, while others provide for movement from one type of roadway
to another. Travel within a thoroughfare network requires that each type of
roadway function according to its intended purpose - access or movement. The
definition of each of these types of roadways is known as functional classification.
Although the Transportation Plan Map only depicts the arterial and freeway level
roadways in Georgetown's thoroughfare network, planning for collector and local
roads must also occur. For the most part, construction of collector and local
roadways will be conducted by private developers according to the requirements
of the development regulations. Maintenance and improvement will then become
they responsibility of the public entity with jurisdiction over the roadway, generally
either the City of Georgetown or Williamson County. This section defines each
of the types of streets within the functional classification system. Design standards
for the roadway classifications, as well as descriptions of the manner in which
planning, development, and maintenance of the system should be accomplished,
can be found in the Transportation Plan Element.
Local streets provide the greatest amount of access to adjacent land uses. Trip
length along the local street is short, with movement from the land use, along the
local road, to a collector road. Therefore, traffic is generally slow and volumes
low. In order to ensure that this is the case, local streets are designed to be short,
curvilinear, and/or discontinuous. Local streets are necessary in all developed
areas.
Collector roads serve both access and movement functions for all land use
types. This Plan designates both residential and non - residential collector roads to
delineate between the types of land use which they serve. Both residential and
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non - residential collectors gather traffic from the local street system and major
traffic generators and feed it onto the arterial streets and freeways. Collector
streets should provide access to individual properties only when traffic generated
on -site is comparable to a local street, such as with a private drive to an apartment
complex or a commercial center. Collector streets can penetrate into
neighborhoods but should not be continuous through them. This will prevent
traffic from using them as if they were arterials.
The function of arterials is to provide for high speed, high volume movement
of traffic between other roadways in the system. The primary arterials in a
thoroughfare system provide a link between the major traffic generators in the city,
as well as between the city and the region. In order to accomplish this, primary
arterials must provide at least one connection to a freeway level road. Secondary
arterials, on the other hand, provide for movement within the community; they
intersect with two or more arterials or several collectors, but do not directly access
freeways. Because they are predominantly used by local traffic, secondary arterials
do not have to be designed to carry as great a volume of traffic as primary
arterials. In any case, access to all arterials from other roadways and driveways
should be carefully planned in order to minimize interference with the movement
of traffic.
Freeways, like arterials, serve the function of movement. However, the
priority for movement along freeways is so great that access to individual
properties is strictly controlled. For this reason, freeways are generally considered
a separate category firm arterials in the functional hierarchy of roadways.
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