TIA - Pumpkin Creek C-Store Resubmittal FINALTraffic Impact Analysis
Pumpkin Creek C-Store
Wilmington, NC
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
i
TABLE OF CONTENTS
1. INTRODUCTION ...............................................................................................................1
1.1. Site Location and Study Area ................................................................................................1
1.2. Proposed Land Use and Site Access ......................................................................................2
1.3. Adjacent Land Uses ...............................................................................................................2
1.4. Existing Roadways ................................................................................................................2
2. EXISTING (2017) PEAK HOUR CONDITIONS ............................................................6
2.1. Existing (2017) Peak Hour Traffic ........................................................................................6
2.2. Analysis of Existing (2017) Peak Hour Traffic .....................................................................6
3. BACKGROUND (2018) PEAK HOUR CONDITIONS ..................................................8
3.1. Ambient Traffic Growth ........................................................................................................8
3.2. Adjacent Development Traffic ..............................................................................................8
3.3. Future Roadway Improvements .............................................................................................8
3.4. Background (2018) Peak Hour Traffic Volumes ...................................................................9
3.5. Analysis of Background (2018) Peak Hour Traffic Conditions ............................................9
4. SITE TRIP GENERATION AND DISTRIBUTION .....................................................13
4.1. Trip Generation ....................................................................................................................13
4.2. Site Trip Distribution and Assignment ................................................................................14
5. COMBINED (2018) TRAFFIC CONDITIONS .............................................................20
5.1. Combined (2018) Peak Hour Traffic Volumes ...................................................................20
5.2. Analysis of Combined (2018) Peak Hour Traffic ................................................................20
6. TRAFFIC ANALYSIS PROCEDURE ............................................................................22
6.1. Adjustments to Analysis Guidelines ....................................................................................23
7. CAPACITY ANALYSIS ...................................................................................................24
7.1. North College Road and Blue Clay Road ............................................................................24
7.2. North College Road and Site Drive 1 ..................................................................................28
7.3. Blue Clay Road and Site Drive 2 .........................................................................................29
8. CONCLUSIONS ................................................................................................................30
9. RECOMMENDATIONS ..................................................................................................32
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
ii
LIST OF FIGURES
Figure 1 – Site Location Map ...................................................................................................... 3
Figure 2 – Preliminary Site Plan .................................................................................................. 4
Figure 3 – Existing Lane Configurations ..................................................................................... 5
Figure 4 – Existing (2017) Peak Hour Traffic ............................................................................. 7
Figure 5 – Projected (2018) Peak Hour Traffic ......................................................................... 10
Figure 6 – Adjacent Development Trips .................................................................................... 11
Figure 7 – Background (2018) Peak Hour Traffic ..................................................................... 12
Figure 8 – Site Trip Distribution ................................................................................................ 15
Figure 9 – Site Trip Assignment ................................................................................................ 16
Figure 10 – Pass-By Trip Distribution ....................................................................................... 17
Figure 11 – Pass-By Trip Assignment ....................................................................................... 18
Figure 12 – Total Site Trips ....................................................................................................... 19
Figure 13 – Combined (2018) Peak Hour Traffic ...................................................................... 21
Figure 14 – Recommended Lane Configurations ...................................................................... 33
LIST OF TABLES
Table 1: Trip Generation Summary ............................................................................................13
Table 2: Highway Capacity Manual – Levels-of-Service and Delay ..........................................22
Table 3: Analysis Summary of North College Road and Blue Clay Road .................................24
Table 4: Analysis Summary of North College Road and Site Drive 1 .......................................28
Table 5: Analysis Summary of Blue Clay Road and Site Drive 2 ..............................................29
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
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TECHNICAL APPENDIX
Appendix A: WMPO Approved Scope
Appendix B: Traffic Counts
Appendix C: Signal Information
Appendix D: Adjacent Development Information
Appendix E: Capacity Calculations – North College Road and Blue Clay Road
Appendix F: Capacity Calculations – North College Road and Site Drive 1
Appendix G: Capacity Calculations – Blue Clay Road and Site Drive 2
Appendix H: SimTraffic Queuing Reports
TRAFFIC IMPACT ANALYSIS
PUMPKIN CREEK C-STORE
WILMINGTON, NORTH CAROLINA
1. INTRODUCTION
The contents of this report present the findings of the Traffic Impact Analysis (TIA) conducted
for the proposed Pumpkin Creek C-Store development to be located in the northwest quadrant
of the intersection of Blue Clay Road and North College Road in Wilmington, North Carolina.
The purpose of this study is to determine the potential impacts to the surrounding
transportation system created by traffic generated by the proposed development, as well as
recommend improvements to mitigate the impacts.
The proposed development, anticipated to be completed in 2018, is assumed to consist of a
5,000 square foot (s.f.) convenience market with gasoline pumps.
The study analyzes traffic conditions during the weekday AM and PM peak hours for the
following scenarios:
Existing (2017) Traffic Conditions
Background (2018) Traffic Conditions
Combined (2018) Traffic Conditions
1.1. Site Location and Study Area
The development is proposed to be located in the northwest quadrant of the intersection of
North College Road and Blue Clay Road in Wilmington, North Carolina. Refer to Figure 1 for
the site location map.
The study area for the TIA was determined through coordination with the Wilmington
Metropolitan Planning Organization (WMPO) and the approved scoping document can be
found in Appendix A. The approved study area consists of the following existing intersection:
North College Road and Blue Clay Road
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
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1.2. Proposed Land Use and Site Access
The proposed development, anticipated to be completed in 2018, is assumed to consist of the
following uses:
5,000 s.f. Convenience Market with Gasoline Pumps
Site access is proposed via a full movement driveway on Blue Clay Road and a right-in/right-
out driveway on North College Road.
1.3. Adjacent Land Uses
The proposed development is located in an area consisting primarily of undeveloped land and
residential development. Cape Fear Community College is located in the southeast quadrant of
the intersection of North College Road and Blue Clay Road.
1.4. Existing Roadways
North College Road (NC 132) is a two-lane roadway running in a north-south direction with a
posted speed limit of 45 miles per hour (mph) within the study area. Based on the most recent
data (2015) from the NCDOT, North College Road had an average annual daily traffic
(AADT) volume of approximately 14,000 vehicles per day (vpd) south of its intersection with
Blue Clay Road.
Blue Clay Road (SR 1318) is a two-lane roadway running in an east-west direction with a
posted speed limit of 55 miles per hour (mph) within the study area. Based on the most recent
data (2015) from the NCDOT, Blue Clay Road had an average annual daily traffic (AADT)
volume of approximately 5,400 vehicles per day (vpd) west of its intersection with North
College Road.
Existing lane configurations (number of traffic lanes on each intersection approach), lane
widths, storage capacities, and other intersection and roadway information was collected
through field reconnaissance by Ramey Kemp & Associates, Inc. (RKA). Refer to Figure 3 for
an illustration of the existing lane configurations within the study area.
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Pumpkin Creek C-Store
Wilmington, NC
N
LEGEND
Proposed Site Location
Study Intersection
Study Area
Site Location Map
Figure 1
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Creekside
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SITESITE
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Pumpkin Creek C-Store
Wilmington, NC
Blue Clay
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Figure 3
Existing
Lane Configurations
LEGEND
Signalized Intersection
Existing Lane
X'Storage (In Feet)
5
SPEED
LIMIT55
SPEEDLIMITXX Posted Speed Limit
75
'
150'
12
5
'
50'
SPEEDLIMIT45
25
0
'
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
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2. EXISTING (2017) PEAK HOUR CONDITIONS
2.1. Existing (2017) Peak Hour Traffic
Existing peak hour traffic volumes were determined based on traffic counts conducted at the
study intersections listed below, in September of 2017 by RKA during a typical weekday AM
(7:00 AM – 9:00 AM) and PM (4:00 PM – 6:00 PM) peak periods:
North College Road and Blue Clay Road
Refer to Figure 4 for existing (2017) weekday AM and PM peak hour traffic volumes. A copy
of the count data is located in Appendix B of this report. It is worth noting that the count was
performed when school was in session.
2.2. Analysis of Existing (2017) Peak Hour Traffic
The existing (2017) weekday AM and PM peak hour traffic volumes were analyzed to
determine the current levels of service at the study intersections under existing roadway
conditions. Signal information was obtained from NCDOT and is included in Appendix C. The
results of the analysis are presented in Section 7 of this report.
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
Blue Clay
Road
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Blue Clay
Road
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Figure 4
Existing (2017)
Peak Hour Traffic
LEGEND
Signalized Intersection
X / Y AM / PM Peak Hour Traffic
11
7
/
3
2
38
9
/
2
6
7
71
/
3
6
7
19/27205/69243/164
11
3
/
7
9
19
7
/
4
1
9
27
5
/
2
2
9
28/104120/15963/105
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
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3. BACKGROUND (2018) PEAK HOUR CONDITIONS
In order to account for growth of traffic and subsequent traffic conditions at a future year,
background traffic projections are needed. Background traffic is the component of traffic due
to the growth of the community and surrounding area that is anticipated to occur regardless of
whether or not the proposed development is constructed. Background traffic is comprised of
existing traffic growth within the study area and additional traffic created as a result of
adjacent approved developments.
3.1. Ambient Traffic Growth
Through coordination with the WMPO, it was determined that an annual growth rate of 1%
would be used to generate projected (2018) weekday AM and PM peak hour traffic volumes.
Refer to Figure 5 for projected (2018) peak hour traffic.
3.2. Adjacent Development Traffic
Through coordination with the WMPO, Cape Fear Community College expansion was
identified to be included as an adjacent development in this study. This development is located
southeast of the intersection of North College Road and Blue Clay Road in Wilmington, NC. A
TIA was completed by Davenport in July 2013. According to this TIA the Cape Fear
Community College expansion will have a Phase 1 buildout year of 2015 and a full buildout
year of 2033. For purposes of this analysis and with approval from the WMPO, only Phase 1
was taken into account as this phase is not fully operational at the time of this study. The Phase
1 expansion is expected to consist of a 30,000 s.f. academic building and a 108,000 s.f.
academic building. Site traffic from this development was distributed through the study area
according to the approved trip generation and trip distribution from the Cape Fear Community
College TIA. Adjacent development trips are shown in Figure 6. Adjacent development
information can be found in Appendix D.
3.3. Future Roadway Improvements
Based on coordination with the WMPO, it was determined there were no future roadway
improvements to consider with this study.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
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3.4. Background (2018) Peak Hour Traffic Volumes
The background (2018) traffic volumes were determined by projecting the existing (2017) peak
hour traffic to the year 2018, and adding the adjacent development trips. Refer to Figure 7 for
an illustration of the background (2018) peak hour traffic volumes at the study intersections.
3.5. Analysis of Background (2018) Peak Hour Traffic Conditions
The background (2018) AM and PM peak hour traffic volumes at the study intersections were
analyzed with existing geometric roadway conditions and traffic control. The analysis results
are presented in Section 7 of this report.
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Pumpkin Creek C-Store
Wilmington, NC
Blue Clay
Road
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Blue Clay
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Figure 5
Projected (2018)
Peak Hour Traffic
10
LEGEND
Signalized Intersection
X / Y AM / PM Peak Hour Traffic
11
8
/
3
2
39
3
/
2
7
0
72
/
3
6
19/27207/70245/166
11
4
/
8
0
19
9
/
4
2
3
27
8
/
2
3
1
28/105121/16164/106
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Pumpkin Creek C-Store
Wilmington, NC
Blue Clay
Road
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Blue Clay
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Figure 6
Peak Hour Adjacent
Development Trips
11
LEGEND
Signalized Intersection
X / Y AM / PM Peak Hour Adjacent Development Trips
42
/
4
2
9/2312/3110/26
45
/
4
5
54/54
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Pumpkin Creek C-Store
Wilmington, NC
Blue Clay
Road
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Blue Clay
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Figure 7
Background (2018)
Peak Hour Traffic
12
LEGEND
Signalized Intersection
X / Y AM / PM Peak Hour Traffic
11
8
/
3
2
39
3
/
2
7
0
11
4
/
7
8
28/50219/101255/192
11
4
/
8
0
19
9
/
4
2
3
32
3
/
2
7
6
28/105175/21564/106
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
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4. SITE TRIP GENERATION AND DISTRIBUTION
4.1. Trip Generation
The proposed development is assumed to consist of a 5,000 s.f. convenience market with
gasoline pumps. Average weekday daily, AM peak hour, and PM peak hour trips for the
proposed development were estimated using methodology contained within the ITE Trip
Generation Manual, 9th Edition. Table 1 provides a summary of the trip generation potential
for the site.
Table 1: Trip Generation Summary
Land Use
(ITE Code) Intensity
Daily
Traffic
(vpd)
AM Peak Hour
Trips (vph)
PM Peak Hour
Trips (vph)
Enter Exit Enter Exit
Convenience Market with Gasoline Pumps
(853) 5,000 s.f. 4,300 103 102 128 127
Pass-By Trips: (63% AM, 66% PM) 1,7001 65 65 84 84
Total Primary Trips 2,600 38 37 44 43
1. Weekday 24 hour volumes calculated based on 10% of weekday 24 hour volumes occurring during the PM
peak hour period.
It is estimated that the proposed development will generate approximately 4,300 total site trips
on the roadway network during a typical 24-hour weekday period. Of the daily traffic volume,
it is anticipated that 205 trips (103 entering and 102 exiting) will occur during the AM peak
hour and 255 (128 entering and 127 exiting) will occur during the PM peak hour.
Pass-by trips were taken into consideration in this study. Pass-by trips are made by the traffic
already using the adjacent roadway, entering the site as an intermediate stop on their way to
another destination. Pass-by trips are expected to account for approximately 1,700 daily trips,
of which it is expected that 130 trips (65 entering and 65 exiting) will occur during the
weekday AM peak hour and 168 trips (84 entering and 84 exiting) will occur during the PM
peak hour. It should be noted that the pass-by trips were balanced, as it is likely that these trips
would enter and exit in the same hour.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
14
The total primary site trips are the calculated site trips after the reduction for internal capture
and pass-by trips. Primary site trips are expected to generate approximately 2,600 site trips
during a typical 24-hour weekday period. Of the daily traffic volume it is anticipated that 75
trips (38 entering and 37 exiting) will occur during the AM peak hour and 87 trips (44 entering
and 43 exiting) will occur during the PM peak hour.
4.2. Site Trip Distribution and Assignment
Trip distribution percentages used in assigning site traffic for this development were estimated
based on a combination of existing traffic patterns, population centers adjacent to the study
area, and engineering judgment. It is estimated that trips will be distributed as follows:
35% to/from the south via North College Road
25% to/from the north via North College Road
25% to/from the west via Blue Clay Road
15% to/from the east via Blue Clay Road
The site trip distribution is shown in Figure 8. Refer to Figure 9 for the primary site trip
assignment.
The pass-by site trips were distributed based on existing traffic patterns with consideration
given to the proposed driveway access and site layout. Refer to Figure 10 for the pass-by site
trip distribution. Pass-by site trips are shown in Figure 11.
The total site trips were determined by adding the primary site trips and the pass-by site trips.
Refer to Figure 12 for the total peak hour site trips at the study intersections. It is worth noting
these distributions were reviewed and approved by the WMPO prior to the submittal of this
study.
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
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Figure 8
Site Trip Distribution
X%
(Y%)
XX%
15%
Entering Trip Distribution
Exiting Trip Distribution
Regional Trip Distribution
LEGEND
Signalized Intersection
Unsignalized Intersection
Right-In/Right-Out Intersection
15
35%
(1
5
%
)
(1
5
%
)
25%
35
%
(25%)(10%)(20%)
(30%)
(2
5
%
)
25
%
25%
(1
5
%
)
(5
5
%
)
60%
15%
25%
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
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Figure 9
Primary Site
Trip Assignment
LEGEND
Signalized Intersection
Unsignalized Intersection
X / Y AM / PM Peak Hour Site Trips
Right-In/Right-Out Intersection
16
5/
7
6/
6
10/11
13
/
1
5
9/114/47/9
11/13
9/
1
1
9/
1
1
6/
6
20
/
2
4
23/26
6/7
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
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X% / Y%AM / PM Pass-By Trip Distribution
LEGEND
Signalized Intersection
Unsignalized Intersection
Pass-By
Trip Distribution
Figure 10
17
-5
%
/
-
5
%
25%/15%
30
%
/
2
0
%
-3
0
%
/
-
2
0
%
20
%
/
1
5
%
55
%
/
7
0
%
55%/60%-20%/-15%
15%/20%-15%/-20%
-5%/-5%15%/15%-10%/-10%
15%/25%15%/15%10%/10%
25
%
/
3
5
%
-1
0
%
/
-
2
0
%
-1
5
%
/
-
1
5
%
Right-In/Right-Out Intersection
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
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Figure 11
Pass-By
Trip Assignment
18
-3
/
-
4
-3/-410/13-7/-8
16
/
2
9
-7
/
-
1
7
-9
/
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1
3
10/219/137/8
16/13
19
/
1
7
-1
9
/
-
1
7
13
/
1
2
36
/
5
9
36/50-13/-12
10/17-10/-17
X / Y AM / PM Pass-By Trips
LEGEND
Signalized Intersection
Unsignalized Intersection
Right-In/Right-Out Intersection
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
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Figure 12
Total Site
Trip Assignment
LEGEND
Signalized Intersection
Unsignalized Intersection
X / Y AM / PM Peak Hour Traffic
19
-3
/
-
4
5/
7
6/
6 -3/-420/24-7/-8
29
/
4
4
-7
/
-
1
7
-9
/
-
1
3
19/3213/1714/17
27/26
9/
1
1
28
/
2
8
-1
9
/
-
1
7
19
/
1
8
56
/
8
3
59/76-13/-12
16/24-10/-17
Right-In/Right-Out Intersection
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
20
5. COMBINED (2018) TRAFFIC CONDITIONS
5.1. Combined (2018) Peak Hour Traffic Volumes
To estimate traffic conditions with the site fully built-out, the total site trips were added to the
background (2018) traffic volumes to determine the combined (2018) traffic volumes. Refer to
Figure 13 for an illustration of the combined (2018) peak hour traffic volumes with the
proposed site fully developed.
5.2. Analysis of Combined (2018) Peak Hour Traffic
Study intersections were analyzed with the combined (2018) traffic volumes using the same
methodology previously discussed for existing and background traffic conditions. Intersections
were analyzed with improvements necessary to accommodate future traffic volumes. The
results of the capacity analysis for each intersection are presented in Section 7 of this report.
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
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2
Figure 13
Combined (2018)
Peak Hour Traffic
LEGEND
Signalized Intersection
Unsignalized Intersection
X / Y AM / PM Peak Hour Traffic
21
11
5
/
2
8
39
8
/
2
7
7
12
0
/
8
4
25/46239/125248/184
14
3
/
1
2
4
19
2
/
4
0
6
31
4
/
2
6
3
47/137188/23278/123
27/26
26
4
/
5
9
0
28
/
2
8
60
6
/
3
6
3
19
/
1
8
56
/
8
3
59/76438/201
16/24257/409
Right-In/Right-Out Intersection
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
22
6. TRAFFIC ANALYSIS PROCEDURE
Study intersections were analyzed using the methodology outlined in the 2010 Highway
Capacity Manual (HCM) published by the Transportation Research Board. Capacity and level
of service are the design criteria for this traffic study. A computer software package, Synchro
(Version 9.1), was used to complete the analyses for most of the study area intersections.
Please note that the unsignalized capacity analysis does not provide an overall level of service
for an intersection; only delay for an approach with a conflicting movement.
The HCM defines capacity as “the maximum hourly rate at which persons or vehicles can
reasonably be expected to traverse a point or uniform section of a lane or roadway during a
given time period under prevailing roadway, traffic, and control conditions.” Level of service
(LOS) is a term used to represent different driving conditions, and is defined as a “qualitative
measure describing operational conditions within a traffic stream, and their perception by
motorists and/or passengers.” Level of service varies from Level “A” representing free flow, to
Level “F” where breakdown conditions are evident. Refer to Table 2 for HCM levels of service
and related average control delay per vehicle for both signalized and unsignalized
intersections. Control delay as defined by the HCM includes “initial deceleration delay, queue
move-up time, stopped delay, and final acceleration delay”. An average control delay of 50
seconds at a signalized intersection results in LOS “D” operation at the intersection.
Table 2: Highway Capacity Manual – Levels-of-Service and Delay
UNSIGNALIZED INTERSECTION SIGNALIZED INTERSECTION
LEVEL OF
SERVICE
AVERAGE CONTROL
DELAY PER VEHICLE
(SECONDS)
LEVEL OF
SERVICE
AVERAGE CONTROL
DELAY PER VEHICLE
(SECONDS)
A
B
C
D
E
F
0-10
10-15
15-25
25-35
35-50
>50
A
B
C
D
E
F
0-10
10-20
20-35
35-55
55-80
>80
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
23
6.1. Adjustments to Analysis Guidelines
Capacity analysis at all study intersections was completed according to the NCDOT
Congestions Management Guidelines. A summary of adjustments to these guidelines made
throughout the analysis is provided below:
For the analysis of the existing signalized intersection at North College Road and Blue
Clay Road, existing signal plans were obtained from NCDOT. The existing settings
were used in the existing (2017) Synchro analysis. It should be noted that both the
eastbound and westbound approaches have a small detector loop for the right-turn
movement, although neither have a designated right-turn lane striped. Through
coordination with the WMPO, these detector loops were not included in the analysis
model due to due to software limitations. It should be noted that the eastbound and
westbound approaches likely operate as though having a small right-turn lane in field
conditions, thus necessitating the additional detection loops.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
24
7. CAPACITY ANALYSIS
7.1. North College Road and Blue Clay Road
The existing signalized intersection of North College Road and Blue Clay Road was analyzed
under existing (2017), background (2018), and combined (2018) traffic conditions with the
lane configurations and traffic control shown in Table 3. Refer to Table 3 for a summary of the
analysis results. Refer to Appendix E for the Synchro capacity analysis reports.
Table 3: Analysis Summary of North College Road and Blue Clay Road
ANALYSIS
SCENARIO
LANE
GROUP
Weekday AM Peak Hour Weekday PM Peak Hour
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Approach
(sec)
Overall
(sec)
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Approach
(sec)
Overall
(sec)
Existing
(2017)
Conditions
EBL
EBT/R
28/149
--
B
C
16
33
C
(31)
C
(22)
86/150
--
B
D
18
36
C
(31)
C
(24)
WBL
WBT/R
169/178
--
C
B
23
17
C
(20)
122/156
--
B
B
19
16
B
(18)
NBL
NBT
NBR
105/125
--
155/140
C
C
B
27
24
14
B
(20)
56/162
--
124159
B
C
B
16
35
13
C
(26)
SBL
SBT/R
46/88
--
B
C
13
22
C
(21)
27/44
--
B
B
13
18
B
(17)
Background
(2018)
Conditions
EBL
EBT/R
29/149
--
B
C
15
34
C
(32)
D
(46)
93/150
--
C
D
20
54
D
(46)
D
(39)
WBL
WBT/R
369/250
--
F
B
185
17
F
(102)
295/245
--
F
B
110
19
E
(70)
NBL
NBT
NBR
116/140
--
197/228
C
C
B
35
29
19
C
(25)
55/174
--
162/350
B
D
B
14
40
15
C
(29)
SBL
SBT/R
143/224
--
D
C
46
25
C
(29)
99/91
--
D
B
48
16
C
(22)
Combined
(2018)
Conditions
EBL
EBT/R
43/149
--
B
D
16
37
C
(34)
D
(45)
117/149
--
C
E
21
66
D
(54)
D
(39)
WBL
WBT/R
361/250
--
F
B
175
18
F
(94)
276/250
--
F
B
96
19
E
(59)
NBL
NBT
NBR
177/174
--
190/138
D
C
B
51
29
19
C
(29)
85/174
--
153/117
B
D
B
17
40
15
C
(28)
SBL
SBT/R
153/143
--
D
C
47
25
C
(29)
104/96
--
D
B
47
16
C
(23)
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
25
Table 3 (continued): Analysis Summary of North College Road and Blue Clay Road
ANALYSIS
SCENARIO
LANE
GROUP
Weekday AM Peak Hour Weekday PM Peak Hour
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Approach
(sec)
Overall
(sec)
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Approach
(sec)
Overall
(sec)
Combined
(2018)
Conditions –
Improved
EBL
EBT/R
43/149
--
B
E
19
75
E
(67)
D
(49)
96/149
--
B
E
17
55
D
(45)
D
(40)
WBL
WBT/R
307/219
--
E
C
77
21
D
(49)
227/162
--
E
B
62
16
D
(40)
NBL
NBT
NBR
206/175
--
186/194
F
C
B
88
27
14
C
(34)
174/175
--
157/350
E
D
B
64
39
15
C
(35)
SBL
SBT/R
128/143
--
D
E
52
58
E
(57)
119/143
--
E
D
57
40
D
(43)
For the analysis of the existing signalized intersection at North College Road and Blue Clay
Road, existing signal plans were obtained from NCDOT. The existing settings were used in
the Synchro analysis for existing traffic scenarios as shown in Table 3. Capacity Analysis
indicates the intersection is expected to operate at an overall LOS C during both weekday AM
and PM peak hours. It should be noted that both the eastbound and westbound approaches have
a small detector loop for the right-turn movement although neither have a designated right-turn
lane striped. Through coordination with the WMPO, these detector loops were not included in
the analysis model due to software limitations. It should be noted that the eastbound and
westbound approaches likely operate as though having a small right-turn lane in field
conditions, thus necessitating the additional detection loops.
The westbound and southbound left-turn movements currently operate as protected-permitted
phasing; per Congestion Management Guidelines, they should be analyzed as protected-only
phasing for all future scenarios. Capacity analysis of background (2018) and combined (2018)
traffic conditions indicates the intersection of North College Road and Blue Clay Road is
expected to operate at an overall LOS D during the weekday AM and PM peak hours.
Based on WMPO standards, improvements are required for approaches at intersections if
background to combined traffic conditions increase in delay by 25% or more, the LOS
degrades by at least one level, or the LOS is an F. The westbound approach meets this
threshold, operating at a LOS F during the weekday AM peak hour; however, from background
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
26
(2018) to combined (2018) traffic conditions the westbound approach decreases in delay by 8
seconds during the weekday AM peak hour. This is not uncommon for intersections operating
at acceptable levels of service because there is available capacity. The westbound left-turn
movement is more heavily traveled, removing the pass-by trips from this movement and
adding them to the westbound thru movement decreases the delay per vehicle and ultimately
the overall approach delay. No improvements by the developer are recommended for this
intersection.
Per the FHWA Signalized Intersections: An Informational Guide, protected phasing treatment
should be implemented if the cross product of the left-turn movement and opposing (through)
traffic is greater than 45,000 for a left-turn movement that crosses 1 opposing lane of traffic.
Under combined (2018) traffic conditions, the cross-product of the northbound left-turn
movement is expected to be approximately 56,900 during the weekday AM peak hour and
protected phasing treatment should be recommended. Per Congestion Management Guidelines,
the northbound left-turn movement was analyzed as protected-only phasing for combined
(2018) improved traffic conditions. It should be noted that due to this change in phasing, the
cycle length and signal timings were optimized in the Synchro software. It is recommended
that a signal modification plan be developed by the NCDOT. The results of the analyses
performed for these conditions is shown in Table 3 as “Improved”. Under combined (2018)
improved traffic conditions, the intersection is expected to operate at an overall LOS D during
both the weekday AM and PM peak hours.
The addition of the northbound left-turn movement protected phasing treatment increased the
overall delay for the intersection by 6 seconds during the weekday AM peak hour and 1 second
during the weekday PM peak hour. The exclusive protected-only phase assigned to the
northbound left-turn movement increases the delay for the southbound through and right-turn
movements, increasing the overall southbound approach delay and ultimately the overall
intersection delay. Additionally, the change in cycle length and signal timings improved the
LOS for the westbound approach; however, the additional time given to the westbound left-
turn movement increases the delay for the eastbound through and right-turn movements,
increasing the overall eastbound approach delay.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
27
It should be noted that under all traffic conditions, right-turns-on-red were turned off, although
field conditions allow for right-turns-on-red for all approaches. Additionally, under all future
traffic conditions, protected-permitted phasing was analyzed as protected-only phasing. Due to
this, the intersection is expected to operate with less delay for all scenarios than shown in
Table 3.
The northbound left-turn lane is expected to operate at an acceptable LOS during the weekday
AM and PM peak hours under the existing Dallas permitted signal phasing; however, based on
the cross product rule for protected phasing treatment, it is recommended for NCDOT to
change the northbound left-turn movement to permitted-protected phasing and develop a signal
modification plan.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
28
7.2. North College Road and Site Drive 1
The proposed unsignalized intersection of North College Road and Site Drive 1 was analyzed
under combined (2018) traffic conditions as a right-in/right-out intersection. Refer to Table 4
for a summary of the analysis results. Refer to Appendix F for the Synchro capacity analysis
reports.
Table 4: Analysis Summary of North College Road and Site Drive 1
ANALYSIS
SCENARIO
LANE
GROUP
Weekday AM Peak Hour Weekday PM Peak Hour
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Overall
(sec)
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Overall
(sec)
Combined
(2018)
Conditions
EBR 5*/82 B1 14
N/A
3*/63 B1 11
N/A NBT -- -- -- -- -- --
SBT
SBR
--
--
--
--
--
--
--
--
--
--
--
--
1. Level of service for minor-street approach.
* Due to limitations with the HCM 2010 TWSC reporting, a vehicle length of 25 feet was used to determine the
95th percentile queue in feet.
Capacity analysis of combined (2018) traffic conditions indicates the minor-street approach at
the intersection of North College Road and Site Drive 1 are expected to operate at LOS B
during both weekday AM and PM peak hours. A southbound right-turn lane with 25 feet of
storage and appropriate taper is recommended at this intersection due to the traffic volumes
along the mainline.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
29
7.3. Blue Clay Road and Site Drive 2
The proposed unsignalized intersection of Blue Clay Road and Site Drive 2 was analyzed
under combined (2018) traffic conditions with proposed lane configurations and traffic control.
Refer to Table 5 for a summary of the analysis results. Refer to Appendix G for the Synchro
capacity analysis reports.
Table 5: Analysis Summary of Blue Clay Road and Site Drive 2
ANALYSIS
SCENARIO
LANE
GROUP
Weekday AM Peak Hour Weekday PM Peak Hour
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Overall
(sec)
Queue
95th / Max
(ft)
Lane
LOS
Delay
(sec)
Overall
(sec)
Combined (2018)
Conditions
EBL/T -- A1 8
N/A
-- A1 8
N/A WBT
WBR
--
--
--
--
--
--
--
--
--
--
--
--
SBL/R 20*/186 C2 17 28*/188 C2 17
1. Level of service for major-street left-turn movement.
2. Level of service for minor-street approach.
* Due to limitations with the HCM 2010 TWSC reporting, a vehicle length of 25 feet was used to determine the
95th percentile queue in feet.
Capacity analysis of combined (2018) traffic conditions indicates the major-street left-turn
movement at the intersection of Blue Clay Road and Site Drive 2 is expected to operate at LOS
A during both weekday AM and PM peak hours. The minor-street approach is expected to
operate at an LOS C during both weekday AM and PM peak hours. A westbound right-turn
lane with 50 feet of storage and appropriate taper is recommended at this intersection due to
the traffic volumes along the mainline.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
30
8. CONCLUSIONS
This Traffic Impact Analysis was conducted to determine the potential traffic impacts of the
proposed Pumpkin Creek C-Store, located in the northwest quadrant of the intersection of
North College Road and Blue Clay Road in Wilmington, North Carolina. The proposed
development, anticipated to be completed in 2018, is assumed to consist of a 5,000 square foot
convenience market with gasoline pumps. Site access is proposed via one full movement
driveway on Blue Clay Road and a right-in/right-out driveway on North College Road.
The study analyzes traffic conditions during the weekday AM and PM peak hours for the
following scenarios:
Existing (2017) Traffic Conditions
Background (2018) Traffic Conditions
Combined (2018) Traffic Conditions
Trip Generation
It is estimated that the proposed development will generate approximately 4,300 total site trips
on the roadway network during a typical 24-hour weekday period. Of the daily traffic volume,
it is anticipated that 205 trips (103 entering and 102 exiting) will occur during the AM peak
hour and 255 (128 entering and 127 exiting) will occur during the PM peak hour.
Adjustments to Analysis Guidelines
Capacity analysis at all study intersections was completed according to the NCDOT
Congestion Management Guidelines. Refer to section 6.1 of this report for a detailed
description of any adjustments to these guidelines made throughout the analysis.
Intersection Capacity Analysis Summary
All the study area intersections (including the proposed site driveways) are expected to operate
at acceptable levels-of-service under existing and future year conditions with the exception of
the intersections listed below. A summary of the study area intersections that are expected to
need improvements are as follows:
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
31
North College Road and Blue Clay Road
Based on WMPO standards, improvements are required for approaches at intersections if
background to combined traffic conditions increase in delay by 25% or more, the LOS
degrades by at least one level, or the LOS is an F. The westbound approach meets this
threshold, operating at a LOS F during the weekday AM peak hour; however, from background
(2018) to combined (2018) traffic conditions the westbound approach decreases in delay by 8
seconds during the weekday AM peak hour. This is not uncommon for intersections operating
at acceptable levels of service because there is available capacity. The westbound left-turn
movement is more heavily traveled, removing the pass-by trips from this movement and
adding them to the westbound thru movement decreases the delay per vehicle and ultimately
the overall approach delay. No improvements by the developer are recommended for this
intersection.
Traffic Impact Analysis Pumpkin Creek C-Store – Wilmington, North Carolina
32
9. RECOMMENDATIONS
Based on the findings of this study, specific geometric improvements have been identified and
are recommended to accommodate future traffic conditions. See a more detailed description of
the recommended improvements below. Refer to Figure 14 for an illustration of the
recommended lane configuration for the proposed development.
Recommended Improvements by NCDOT
North College Road and Blue Clay Road
Develop a signal modification plan to accommodate the northbound left-turn
movement change in phasing from Dallas permitted to permitted-protected phasing.
Recommended Improvements by Developer
North College Road and Site Drive 1
Provide site access via a right-in/right-out intersection with one ingress lane and
one egress lane.
Provide stop control for Site Drive.
Provide an exclusive southbound right-turn lane on North College Road with 25
feet of storage and appropriate taper.
Blue Clay Road and Site Drive 2
Provide site access via a full movement intersection with one ingress lane and one
egress lane.
Provide stop control for Site Drive.
Provide an exclusive westbound right-turn lane on Blue Clay Road with 50 feet of
storage and appropriate taper.
Scale: Not to Scale
Pumpkin Creek C-Store
Wilmington, NC
SITE
N
Blue Clay
Road
Blue Clay
Road
No
r
t
h
C
o
l
l
e
g
e
Ro
a
d
No
r
t
h
C
o
l
l
e
g
e
Ro
a
d
Site
Drive 1
Si
t
e
Dr
i
v
e
2
Figure 14
Recommended
Lane Configurations
LEGEND
Signalized Intersection
Unsignalized Intersection
Existing Lane
X'Storage (In Feet)
Improvement by Developer
33
75
'
150'
12
5
'
50'
25
'
50'
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