Morrisville Transportation Plan - 2009

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G-1
Appendices
G Crabtree Crossing
Appendix G. Crabtree Crossing Parkway Extension
The following is an encapsulation of the
history and design considerations for the
Crabtree Crossing Parkway Extension
project, which was initially proposed in
draft versions of the 2009 Transportation
Plan. The project would be approximate-
ly 0.3 miles in length, and would connect
Town Hall Drive to the existing Crabtree
Crossing Parkway and the Town of Cary
to the south. Crabtree Crossing Parkway
Extension (CCPE) would be desirable in
terms of providing additional connectiv-
ity to heavily developed residential areas
for local motorists and non-motorists wish-
ing to travel north-south without using the
more heavily traveled alternatives such
as NC 54/Chapel Hill Road.
History . The Crabtree Crossing Parkway Extension has, over time, referred to more than one
section of roadway. In the current context, we refer to the CCPE as the section between
the current terminus of Crabtree Crossing Parkway northward to Morrisville-Carpenter Road
at its current intersection with Town Hall Drive. Figure G.1 illustrates some of the history of
the roadway and its genesis from the Preston subdivisions. The first mention of the CCPE
was on January 12, 1996 when the current Crabtree Crossing Parkway was indicated as a
road to be extended on a set of plans.
The value of this project has been exam-
ined previously, most recently in an analysis
conducted in 2006. The prior traffic analy-
sis was conducted by Parsons Brinckerhoff
Quade & Douglas (PBQ&D, now PB World)
and reported in the June 9, 2006 “Com-
parative Traffic Study: Morrisville-Carpenter
Road Widening vs. Crabtree Crossing Ex-
tension.” The comparisons of the resulting
traffic values assigned to Crabtree Crossing
Parkway Extension from the PBQ&D study
and the 2009 Transportation Plan have
been the source of some confusion, and
the various points of information are sum-
marized in Figure G.2.
Because of the differences explained by
Figure G.2, the resulting traffic volumes
projected for Crabtree Crossing Parkway
Extension are different for the two studies:
6,600 vehicles per day (vpd) for the PBQ&D
study, and approximately 1,500 vpd for the
studies conducted during the planning pro-
cess for the 2009 Transportation Plan.
Influence of Park West Village. One ques-
tion about CCPE has been the influence of additional traffic created by the mixed use
development Park West Village. Figure G.3 illustrates the various dwelling unit (housing)
and employment projections in the Park West Village area from the 2005 and 2035 Triangle
Regional Model, and the 2035 Preferred Scenario developed during the planning process
for the 2009 Transportation and Land Use Plans. Two traffic analysis zones (TAZs) contain
information about future development in the Park West Village Area, and both extend be-
yond the proposed Park West Village site. Through the planning process for the 2009 Trans-
portation and Land Use Plans, the residential and employment densities were adjusted to
reflect the most current understanding of the development potential in this area, including
Park West Village.
Water Quality. A review of wetlands and stream features was conducted for an area
spanning 300 feet centered on the centerline of the proposed new alignment. The Lou-
is Berger Group, Inc. conducted a scoping field view on May 5, 2008.
Wetland areas identified in the field were evaluated for jurisdictional
status by the three-parameter method outlined in the Corps of Engi-
neers Wetland Delineation Manual, Technical Report Y-87-1 (January,
1987). Stream channels were identified by using indicators of Ordinary
High Water Mark (OHWM), the North Carolina Division of Water Quality
(NCDWQ) stream rating method, and the US Army Corps of Engineers
(USACE) stream rating method. Jurisdictional boundaries were not de-
lineated during this field visit; however, positions at key locations of po-
tentially jurisdictional waters were logged in the field with a GPS unit
capable of sub-meter accuracy.
Berger scientists identified six potentially jurisdictional channels within the
study area. Channels identified included the main stem of Crabtree
Creek and multiple unnamed tributaries. One upland ditch draining to
Crabtree Creek was also observed. No potentially jurisdictional wet-
lands were identified during the field review.
Wildlife Habitat. The predominant natural community within the review
area is a bottomland hardwood forest community. The upper canopy
was dominated by red maple (Acer rubrum), green ash (Fraxinus pen-
Figure G.1 General History of the Crabtree Crossing Extension Project
Source: Town of Morrisville Town Council Minutes
Description PBQ&D Study (2006) Transportation Plan/LBG Study (2009)
Reason for Studying
CCPE
Comparing three build alterna-
tives to discern value-benefit of
each alternative
Small part of a much larger study looking
at feasible transportation improvements
throughout the Town
Level of Detail Fine, includes detailed traffic
movement analysis
Coarse, traffic impacts studied at the cor-
ridor level in general
Forecast Year 2008 (from 2006) 2035
Method of Generating
Traffic Volumes
Assumed 2% annual growth rate
at key intersections based on
2003 traffic counts, then 10% re-
duction at Morrisville-Carpenter
Road/NC 54 intersection
Approved Triangle Regional Model using
land use forecasts supplied by the Town of
Morrisville (and Cary)
Method of Distributing
Traffic
Assumed diversions, primarily
from NC 54 / Chapel Hill Road
and some fromclosure of Church
Street
Approved Triangle Regional Model
Cost of Construction Assumes 2006 dollars and value
of materials; possibly assumes
four-lane road and structure
Assumes 2008 dollars and value of mate-
rials; assumes two/three-lane road and
structure
Other Roadway Assump-
tions
Depending on the scenario be-
ingdiscussed, Morrisville-Carpen-
ter Road widened to five lanes
Major roadways are widened, including
Davis Drive, NC 55, NC 54, Western Wake
Freeway, and Morrisville Carpenter Road
Figure G.2 Contrasting the PBQ&D Report and 2009 Transportation Plan
Source: PBQ&D, 2006; The Louis Berger Group, Inc., 2009
1078
1785
Figure G.3 Population and Employment in Park West Village Area
Sources: Triangle Regional Model and 2009 Transportation Plan