HomeMy WebLinkAboutCOTTONWOOD RIDGE SUBDIVISION - PRELIMINARY - 31-94 - SUBMITTAL DOCUMENTS - ROUND 1 - TRAFFIC STUDYin the long range future. Since street frontage improvements will
be required in the short range future, right -turn auxiliary lanes
can be striped on the widened arterial streets in the interim time
period. Center left -turn lanes should be considered wherever
feasible on arterial streets.
Based upon the traffic forecasts shown in Figure 7, the
eastbound left -turn lane at the Shields/Westbury Access/FRCC
intersection should be 35 feet (one foot per peak hour vehicle).
Rounding to a minimum left -turn lane of 50 feet with 90 feet of
taper will allow 50 feet of westbound left -turn lane to the street
access to Cottonwood Ridge from this Westbury Access.
III. Conclusions
The following summarizes the significant findings as a result
of this study:
- Traffic from Cottonwood Ridge and other proposed uses in
the area can be accommodated on the area streets with various
improvements.
- Traffic operation at the area intersections is acceptable.
- At the short range future (1997), the key intersections
operate acceptably, except for eastbound minor street left turns
to Shields Street from the Westbury Access. The eastbound left
turns will experience delays which are common at arterial/local
street intersections with stop sign control. It is recommended
that an eastbound right -turn lane and left -turn signal phases be
implemented at the Harmony/Shields intersection
- At the long range future (2015), the key intersections will
operate acceptably, except for the minor street left turns at the
Shields/Westbury Access/FRCC intersection, which will experience
some delays. It is expected that Harmony Road and Shields Street
will be built to four lane cross sections. The geometry shown in
Figure 8 is recommended, based upon the long range future traffic
forecasts.
II
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RECOMMENDED GEOMETRY (LONG RANGE) Figure 8
Table 4
Long Range (2015) Peak Hour Operation
Level
of Service
1 Intersection
1
AM
PM
Shields/Harmony (signal)
C
C
I(2 SB LT lanes, separate WB and NB RT lanes)
Harmony/Westbury Access (stop sign)
D
NB LT
D
A
A
NB RT
A
A
WB LT
Shields/Westbury Access/FRCC (stop sign)
EB LT/T
E
E
EB RT
A
E
A
E
WB LT/T
A
A
WB RT
B
A
SB LT
A
A
NB LT
Shields/Cottonwood Access (stop sign)
EB LT
D
A
D
A
EB RT
A
A
NB LT
I
r
II
II
9
HARMONY
- 385/990
j'5/15
O O
0 0 LO
OM'
0
+
200/480
- 240/800
150/250
1150 685 - r
-!
5/5 -4 I 900/500
115/90
-
0 0 0
�Lr) 150/105-�
.
000
C" O
N
CO)
0
W
WESTBURY
/
oLn
N LWO
-15/50
000,
WOO
r1` -
NOM.
F.R.C.C.
35/25
NOW
10/5
LO r-
o
1
0
rn
COTTONWOOD j
RIDGE /
00
VC
4
uJ7
/ 1
15/10 -j
}
5/5
AM / PM
» o
Rounded to
Nearest
C)
5 Vehicles.
LONG RANGE PEAK HOUR TRAFFIC Figure 7
Table 3
Short Range (1997) Peak Hour operation
Level
of Service
Intersection
AM
PH
Shields/Harmony (signal)
C
C
(Separate right -turn, through, and left -turn
lanes on all approaches, and left -turn phases
on all approaches)
w
Harmony/Westbury Access (stop sign)
C
NB LT
C
A
A
NB RT
A
A
WB LT
Shields/Westbury Access/FRCC (stop sign)
E
EB LT/T
E
A
A
EB RT
D
D
WB LT/T
A
A
WB RT
A
A
SB LT
A
A
NB LT
Shields/Cottonwood Access (stop sign)
EB LT
D
A
D
A
EB RT
A
A
i NB LT
4
N
HARMONY
AM / PM
� 152/511
/-- 4/15
397 r/
2/3
WESTBURY
N
O
—117/341
°O
—117/434
L
`
80/168
70 42
}
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515f319�
86/45 —�
�
�
00
COTTONWOOD
RIDGE /
N � N
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NOM.
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34/24 �) } I
NOM. o cn �
10/5
0
co
13/8 --/ ) }
3/2 N
rLo
SHORT RANGE PEAK HOUR TRAFFIC
F.R.C.C.
Figure 6
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COTTONWOOD 1
DIVE
/
RIDGEco
COTTONWOOD
RIDGE
ACCESS
13/8
AM / PM
SITE GENERATED TRAFFIC,
PEAK HOUR ASSIGNMENT Figure 5
Access/FRCC with stop sign control, and Shields/Cottonwood Ridge
Access with stop sign control. Figure 5 shows the traffic
assignment of site generated traffic at the key intersections.
Figure 6 shows the short range (1997) peak hour traffic
assignment. This assignment also includes a 3 percent per year
increase in background traffic as described earlier in this report
plus the Westbury generated traffic. Table 3 shows the peak hour
operation at the key intersections. Calculation forms are provided
in Appendix D. All of the key intersections will operate
acceptably with the existing geometrics, except for the eastbound
left turns at the Shields/Westbury Access/FRCC intersection. These
turns will operate at level of service E. While not desirable,
level of service E for minor street left turns is normal at
intersections with arterial streets. As traffic continues to
increase on both Shields Street and Harmony Road, it is recommended
that separate right -turn, through, and left -turn lanes be included
on all legs of the Harmony/Shields intersection. This
recommendation will require provision of an eastbound right -turn
lane. All other approaches currently have the recommended
geometrics. It is also recommended that left -turn signal phases
be included on all approaches.
Figure 7 shows the long range (2015) peak hour traffic
assignment which includes the background traffic on the area
streets. Table 4 shows the peak hour operation at the key
intersections. Calculation forms are provided in Appendix E. By
this future time, it is expected that Harmony Road and Shields
Street will have four lane cross sections as per Fort Collins
arterial street standards. Typically, dual left -turn lanes should
be considered when the left -turn approach volume exceeds 300 per
hour. The southbound left -turn approach volume is projected at
350-400 vehicles during the peak hours. Separate right -turn lanes
should be considered for the south and east approaches. These
recommendations are based upon traffic forecasts. Should travel
patterns or modal split change significantly, these turn lanes may
not be required. Traffic should be monitored to verify these
suggestions. All stop sign controlled intersections will operate
acceptably, except for minor street left -turns at the
Shields/Westbury Access/FRCC intersection. These turns will
operate at level of service E. This type of operation is normal
at stop sign controlled intersections on arterial streets.
0 E. Intersection Geometrics
Figure 8 shows the recommended geometry at the key
intersections in the long range future. According to criteria in
the "Intersection Channelization Design Guide," NCHRP 279, TRB,
1985, right -turn auxiliary lanes are not required. at the Harmony/
Westbury Access intersection, the Shields/Westbury Access/FRCC
intersection, and the Shields/Cottonwood Ridge Access intersection
1 4
t
II
11 TRIP DISTRIBUTION Figure 4
it
iA. Trip Generation
Trip generation estimates for Cottonwood Ridge were obtained
from Trip Generation, 5th Edition, ITE. Table 2 shows trip
generation on a daily and peak hour basis.
B. Background Traffic
Background traffic is defined as the traffic that is and/or
will be on the area streets that is not related to the proposed
development. The intersections considered for the operations
analysis are Harmony/Shields, Harmony/Westbury Access, Shields/
Westbury Access/FRCC, and Shields/Cottonwood Ridge Access.
Background traffic for impacted streets was projected for each
of the future years analyzed (1997 and 2015). Background traffic
was projected to increase at 3 percent per year for the short range
future. This rate of increase is normal for streets and roads in
the City of Fort Collins. It accounts for general traffic growth
and some level of continued development in the vicinity that would
also contribute to traffic growth.
Long range future background traffic was projected using
traffic studies for various developments in this area of Fort
Collins. In addition, daily traffic projections were obtained from
the City of Fort Collins.
C. Trip Distribution
Trip distribution was determined based upon an evaluation of
attractions for home -based productions and the most likely routes
available to travel to those attractions. The directional
distribution of the approaching and departing traffic generated at
the proposed uses is a function of:
- Geographic location within the City of Fort Collins
- Location of employment and business centers which are likely
to attract trips from this area
- Access to the site.
Figure 4 illustrates the trip distribution percentages used in the
subsequent traffic assignments.
D. Traffic Assignment and Intersection Operation
Using the vehicular trip generation estimates presented in
Table 2, the site generated traffic was assigned to the area street
network. The network consisted of Harmony Road, Shields Street,
and the access streets described earlier. The analyzed
intersections were Harmony/Shields with the existing signalization,
Harmony/Westbury Access with stop sign control, Shields/Westbury
3
SITE PLAN
WESTBURY N
NO SCALE
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t,
ACCESS
Figure 3
Table 1
Existing Peak Hour Operation
Level
of Service
Intersection
AM
PM
Shields/Harmony (signal)
B
B
Harmony/Regency (stop sign)
NB LT/T
B
B
NB RT
A
A
SB LT/T
C
C
SB RT
A
A
EB LT
A
A
WB LT
A
A
Shields/Clarendon Hills (stop sign)
WB LT
C
D
WB RT
A
A
SB LT
A
A
Shields/FRCC (stop sign)
WB LT
D
D
WB RT
A
A
SB LT
B
A
Table 2
Trip Generation
Daily A.M.
Peak
P.M.
Peak
Land Use Trips Trips
Trips
Trips
Trips
in
out
in
out
Cottonwood Ridge
70 Single Family D. U. 670 13
39
46
25
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W
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o�
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CD — 59/22 �N t 106/310
145/407 ' -- `�-105/388
f-- 5/13 HARMONY + 66/127
11/5 + 57Y35 }
459/303 --� o 463 286
0/1—� 78/40
N N M
N
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1/94
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d.
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— 5/13
F.R.C.C.
cq
N CLARENDON
-- 76/52 HILLS
13/6 DRIVE
II
N
47 \
�"to
5/94
AM / PM
RECENT PEAK HOUR TRAFFIC Figure 2
I
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Land uses in this area are residential, vacant (agricultural),
and institutional. Residential uses are east, south, and west of
the site. The Front Range Community College is northeast of the
site. Vacant land is north of the site. However, this land will
be the future Westbury residential development.
II. Existing Conditions
Peak hour intersection counts were obtained in 1994. These
counts are shown in Figure 2. Raw data is shown in Appendix A.
Since the peak hour of a residential development occurs at the same
time as the peak hour of the streets, counts were obtained at 7:30-
8:30 AM and 4:30-5:30 PM.
With the existing control at the key intersections, the peak
hour operation is shown in Table 1. This operation is deemed
acceptable. Acceptable operation is defined as level of service
D or better. Descriptions of level of service .from the 1985
Highway Capacity Manual for signalized and unsignalized
intersections are provided in Appendix B. Calculation forms for
the operation shown in Table 1 are provided in Appendix C.
III. Proposed Development
Cottonwood Ridge is a proposed 70 dwelling unit lot
development on a parcel of land south of Harmony Road and west of
Shields Street. A schematic site plan is shown in Figure 3. The
developer of Cottonwood Ridge is proposing to access to a street
within the recently approved Westbury residential development to
the north. The access will be approximately 200-230 feet west of
Shields Street. The street within Westbury intersects both Shields
Street and Harmony Road. In addition, the developer of Cottonwood
Ridge is proposing an access to Shields Street, approximately 1000
feet south of the Shields/Westbury Access/FRCC intersection. This
access is approximately 320 feet south of the Shields/Clarendon
Hills Drive intersection. There is a cul-de-sac street under
construction on the west side of Shields Street, approximately 270
feet south of the proposed Shields/Cottonwood Ridge Access
intersection. There are/wi11 be no conflicting left -turn movements
along Shields Street between Clarendon Hills Drive and the cul-de-
sac.
Two future years were selected for analysis. The short range
future was 1997 and the long range future was 2015. It is assumed
that this development will be built out by 1997.
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SITE LOCATION Figure 1
I. Introduction
Cottonwood Ridge is a proposed residential development located
west of Shields Street and south of Harmony Road in Fort Collins,
Colorado. The site location is shown in Figure 1. This
development is located south of a recently approved residential
development known as Westbury. The "Traffic Impact Study,
Westbury," March 2, 1994 was used as a reference document in
preparing this site access study for Cottonwood Ridge. The
arterial streets which will be impacted by this development are
Harmony Road and Shields Street. The key intersections that will
be impacted are: Harmony/Shields, Harmony/Westbury Access,
Shields/Westbury Access/Front Range Community College Access, and
Shields/Cottonwood Ridge Access.
Harmony Road is classified as a major arterial on the Fort
Collins Master Street Plan. The segment between Shields Street and
College Avenue is three lanes with a rural cross section on the
south side and curb and gutter on the north side. Harmony Road
widens to four lanes with an urban cross section from the railroad
tracks to College Avenue. The segment just north of Front Range
Community College is striped as one eastbound lane and one
westbound lane. West of Shields Street, Harmony Road has a two
lane, rural cross section. There is spot widening at selected
intersections to accommodate auxiliary lanes. There is signal
control at the Harmony/Shields intersection. All other nearby
intersections are stop sign controlled with Harmony Road receiving
the right-of-way. In the future, Harmony Road is expected to have
a four lane cross section with turn lanes at appropriate locations.
Harmony Road is posted at 35 mph in this area.
Shields Street is classified as an arterial on the Fort
Collins Master Street Plan. It is a street of varying width south
of Drake Road. In the general vicinity of the Cottonwood Ridge
site, Shields Street has one lane in each direction and a painted
two-way left -turn median area. It is proposed to have a four lane
urban cross section with turn lanes at appropriate locations in the
future. It is posted at 35 mph near Harmony Road.
Access to Front Range Community College (FRCC) is located on
the east side of Shields Street, approximately 1200 feet south of
Harmony Road. The access to Westbury is proposed to line up with
the FRCC driveway.
Clarendon Hills Drive is a local street serving the Clarendon
Hills residential area. It has an urban cross section with one
lane in each direction. There are other access streets to the
Clarendon Hills area from both Shields Street and Harmony Road.
Regency Drive is a north/south local street, serving the
Platt/Mountainridge Farm area north of Harmony Road and the "Ridge"
area south of Harmony Road.
1
`I
COTTONWOOD RIDGE
SITE ACCESS STUDY
FORT COLLINS, COLORADO
JUNE 1994
Prepared for:
Sanford Thayer, Trustee
1827 Michael Lane
Fort Collins, CO 80526
Prepared by:
MATTHEW J. DELICH, P.E.
3413 Banyan Avenue
Loveland, CO 80538
Phone: 303-669-2061