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TRAFFIC IMPACT
ANALYSIS
FOR
HIGHWAY 421 C-STORE
LOCATED
IN
NEW HANOVER COUNTY, NC
Prepared For:
Encore Real Estate
1646 W Snow Avenue, Suite 63
Tampa, Fl 33606
OCTOBER 2024
DRMP Project No. 24500
Prepared By: GWH
Reviewed By: CTS
TRAFFIC IMPACT
ANALYSIS
FOR
HIGHWAY 421 C-STORE
LOCATED IN
NEW HANOVER COUNTY, NC
Prepared For:
Encore Real Estate
1646 W Snow Avenue, Suite 63
Tampa, Fl 33606
Prepared By:
DRMP, Inc.
License #F-1524
TRAFFIC IMPACT ANALYSIS
HIGHWAY 421 C-STORE
New Hanover County, North Carolina
E XE C UT IVE S UMM AR Y
1. Development Overview
A Traffic Impact Analysis (TIA) was conducted for the proposed Highway 421 C-Store
development in accordance with the North Carolina Department of Transportation (NCDOT)
and Wilmington Urban Area Metropolitan Planning Organization (WMPO) capacity analysis
guidelines. The proposed development is to be located at 3705 N US Highway 421 in New
Hanover County, North Carolina.
The proposed development, anticipated to be completed in 2026, is assumed to consist of
a 19-vehicle fueling position (VFP) convenience store/gas station. Site access is proposed
via two (2), existing, full movement driveways on US 421. Both driveways are (are proposed
to be) aligned with the Mid-Atlantic Roofing Supply Driveways located on the opposite side
of US 421. Construction of the southernmost existing access (Access B) was completed by
the recent warehousing development that is located behind the proposed convenience
store/gas station.
A 13,000 square foot general office building was also analyzed as part of the trip generation
for the proposed site due to the two developments sharing an access. It should be noted
that the proposed convenience store/gas station development and the office development
are to be constructed by different developers and that the proposed location of the office
building is between the aforementioned warehousing development and the proposed
convenience store/gas station.
2. Existing Traffic Conditions
The study area for the TIA was determined through coordination with NCDOT and the WMPO
and consists of the following existing intersections:
• US 421 and Mid Atlantic Roofing Northern Driveway / Existing Access A
• US 421 and Mid Atlantic Roofing Southern Driveway / Existing Access B
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Existing peak hour traffic volumes were determined based on traffic counts conducted at
the existing study intersections, in July 2024 by Burns Service Inc. during the typical
weekday AM (7:00 AM – 9:00 AM) and PM (4:00 PM – 6:00 PM) peak periods. It should be
noted that traffic data collection during the summer was approved by NCDOT/WMPO during
scoping.
3. Future Traffic Conditions
Through coordination with NCDOT and WMPO, it was determined that an annual growth rate
of 1% would be used to generate 2026 no-build weekday AM and PM peak hour traffic
volumes. Based on coordination with NCDOT and WMPO, there were no approved adjacent
developments to be considered in this study.
Based on coordination with NCDOT and WMPO, it was determined that there were no future
roadway improvements to consider with this study; however, it should be noted that a
southbound right turn lane, along US 421, is proposed to be constructed at the Existing
Access B by the warehousing development (mentioned in section 1 of the executive
summary). Construction of this turn lane is expected to be completed prior to completion
of the proposed site; therefore, this turn lane was analyzed as a background improvement
under 2026 no-build and 2026 build traffic conditions.
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4. Site Trip Generation
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, 11th Edition. Table E-1 provides a summary of the trip generation potential for the
site.
Table E-1: Site Trip Generation
Land Use
(ITE Code) Intensity
Daily
Traffic
(vpd)
Weekday
AM Peak Hour
Trips (vph)
Weekday
PM Peak Hour
Trips (vph)
Enter Exit Enter Exit
General Office Building
(710) 13,000 sq. ft 198 25 4 5 26
Convenience Store/Gas Station
(945) 19 VFP 4,886 257 257 216 216
Total Trips 5,084 282 261 221 242
*Pass-By Trips:
Convenience Store/Gas Station
(76% AM, 75% PM)
-79 -79 -69 -69
Total Primary Trips 203 182 152 173
*Limited to 10% of the adjacent street traffic.
5. Capacity Analysis Summary
The analysis considered weekday AM and PM peak hour traffic for 2024 existing, 2026 no-
build, and 2026 build traffic conditions. Refer to Section 7 of the TIA for the capacity analysis
summary performed at each study intersection.
6. 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 E-1 for an illustration
of the recommended lane configurations.
2026 Recommended Improvements by Developer
US 421 and Mid Atlantic Roofing Northern Driveway / Existing Access A
• Construct a southbound right turn lane on US 421 with 100 feet of storage and
appropriate taper length.
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• Modify the striping of the existing two-way left-turn lane (TWLTL) on US 421, if
necessary.
US 421 and Mid Atlantic Roofing Southern Driveway / Existing Access B
• Construct an eastbound left turn lane on the Existing Access B that provides a
minimum of 125 feet of left turn stacking for the egress of Access B.
• Modify the striping of the existing two-way left-turn lane (TWLTL) on US 421, if
necessary.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
*Modify the striping of the existing TWLTL, if
necesarry.
*
LEGEND
Unsignalized Intersection
Existing Lane
X'Storage (In Feet)
Improvements by Developer
10
0
'
Figure E-1
2026 Recommended
Lane Configurations
vii
TW
L
T
L
TW
L
T
L
TW
L
T
L
10
0
'
TW
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T
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*
125'
DR
O
P
L
A
N
E
Improvements by Others
viii | P a g e
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 ............................................................................................ 3
Table 1: Existing Roadway Inventory ......................................................................... 3
2. 2024 EXISTING PEAK HOUR CONDITIONS ..................................................... 7
2.1. 2024 Existing Peak Hour Traffic Volumes.............................................................. 7
2.2. Analysis of Existing Peak Hour Traffic Conditions ................................................... 7
3. 2026 NO-BUILD PEAK HOUR CONDITIONS ..................................................... 9
3.1. Ambient Traffic Growth ...................................................................................... 9
3.2. Adjacent Development Traffic ............................................................................. 9
3.3. Future Roadway Improvements .......................................................................... 9
3.4. 2026 No-Build Peak Hour Traffic Volumes ............................................................. 9
3.5. Analysis of No-Build Peak Hour Traffic Conditions ................................................ 10
4. SITE TRIP GENERATION AND DISTRIBUTION .............................................. 12
4.1. Trip Generation ............................................................................................... 12
Table 2: Trip Generation Summary .......................................................................... 12
4.2. Site Trip Distribution and Assignment ................................................................ 13
5. 2026 BUILD TRAFFIC CONDITIONS .............................................................. 19
5.1. 2026 Build Peak Hour Traffic Volumes ................................................................ 19
5.2. Analysis of Build Peak Hour Traffic Conditions ..................................................... 19
6. TRAFFIC ANALYSIS PROCEDURE .................................................................. 21
Table 3: Highway Capacity Manual – Levels-of-Service and Delay ............................... 21
6.1. Adjustments to Analysis Guidelines ................................................................... 21
7. CAPACITY ANALYSIS.................................................................................... 22
7.1. US 421 and Mid Atlantic Roofing Northern Driveway / Existing Access A ................. 23
Table 4: Analysis Summary of US 421 and Mid Atlantic Roofing Northern Driveway / Existing
Access A .................................................................................................... 23
7.2. US 421 and Mid Atlantic Roofing Southern Driveway / Existing Access B ................ 25
Table 5: Analysis Summary of US 421 and Mid Atlantic Roofing Southern Driveway / Existing
Access B .................................................................................................... 25
Table 5: Analysis Summary of US 421 and Mid Atlantic Roofing Southern Driveway / Existing
Access B - Continued ................................................................................... 26
8. CONCLUSIONS ............................................................................................. 28
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9. RECOMMENDATIONS .................................................................................... 29
LIST OF FIGURES
Figure 1 – Site Location Map .......................................................................................... 4
Figure 2 – Preliminary Site Plan ..................................................................................... 5
Figure 3 – Existing Lane Configurations ........................................................................... 6
Figure 4 – 2024 Existing Peak Hour Traffic ...................................................................... 8
Figure 5 – 2026 No-Build Peak Hour Traffic ................................................................... 11
Figure 6 – Proposed Site Trip Distribution ...................................................................... 14
Figure 7 – Proposed Site Trip Assignment ...................................................................... 15
Figure 8 – Proposed Site Pass-By Trip Distribution .......................................................... 16
Figure 9 – Proposed Site Pass-by Trip Assignment .......................................................... 17
Figure 10 – Proposed Site Total Trip Assignment ............................................................ 18
Figure 11 – 2026 Build Peak Hour Traffic ....................................................................... 20
Figure 12 – 2026 Recommended Lane Configurations ..................................................... 30
LIST OF TABLES
Table 1: Existing Roadway Inventory .............................................................................. 3
Table 2: Trip Generation Summary ............................................................................... 12
Table 3: Highway Capacity Manual – Levels-of-Service and Delay .................................... 21
Table 4: Analysis Summary of US 421 and Mid Atlantic Roofing Northern Driveway / Existing
Access A .............................................................................................................. 23
Table 5: Analysis Summary of US 421 and Mid Atlantic Roofing Southern Driveway / Existing
Access B .............................................................................................................. 25
Table 5: Analysis Summary of US 421 and Mid Atlantic Roofing Southern Driveway / Existing
Access B - Continued ............................................................................................ 26
TECHNICAL APPENDIX
Appendix A: Approved Scoping Documentation
Appendix B: Traffic Count Data
Appendix C: Capacity Analysis Calculations and Turn Lane Warrants – US 421 and
Mid Atlantic Roofing Northern Driveway / Existing Access A
Appendix D: Capacity Analysis Calculations and Turn Lane Warrants – US 421 and Mid
Atlantic Roofing Southern Driveway / Existing Access B
Appendix E: SimTraffic Queueing Analysis
T R AF F IC IM P AC T ANAL Y S IS
Highway 421 C-Store
New Hanover County, North Carolina
1. INTRODUCTION
The contents of this report present the findings of the Traffic Impact Analysis (TIA)
conducted for the proposed Highway 421 C-Store to be located at 3705 N US Highway
421 in New Hanover County, 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 2026, is assumed to consist of
a 19-vehicle fueling position (VFP) convenience store/gas station. A 13,000 square foot
general office building was also analyzed as part of the trip generation for the proposed
site due to the two developments sharing an access. It should be noted that the proposed
convenience store/gas station development and the office development are to be
constructed by different developers.
The study analyzes traffic conditions during the weekday AM and PM peak hours for the
following scenarios:
• 2024 Existing Traffic Conditions
• 2026 No-Build Traffic Conditions
• 2026 Build Traffic Conditions
1.1. Site Location and Study Area
The development is proposed to be located at 3705 N US Highway 421 in New Hanover
County, North Carolina. Refer to Figure 1 for the site location map. The study area for the
TIA was determined through coordination with the North Carolina Department of
Transportation (NCDOT) and the Wilmington Urban Area Metropolitan Planning
Organization (WMPO) and consists of the following existing intersections:
• US 421 and Mid Atlantic Roofing Northern Driveway / Existing Access A
• US 421 and Mid Atlantic Roofing Southern Driveway / Existing Access B
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Refer to Appendix A for the approved scoping documentation.
1.2. Proposed Land Use and Site Access
The proposed development is assumed to consist of a 19-vehicle fueling position (VFP)
convenience store/gas station.
Site access is proposed via two (2), existing, full movement driveways on US 421. Both
driveways are (are proposed to be) aligned with the Mid-Atlantic Roofing Supply Driveways
located on the opposite side of US 421. Construction of the southernmost existing access
(Access B) was completed by the recent warehousing development that is located behind
the proposed convenience store/gas station. Refer to Figure 2 for a copy of the preliminary
site plan.
1.3. Adjacent Land Uses
The proposed development is located in an area consisting primarily of industrial
development.
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1.4. Existing Roadways
Existing lane configurations (number of traffic lanes on each intersection approach), speed
limits, storage capacities, and other intersection and roadway information within the study
area are shown in Figure 3. Table 1 provides a summary of this information, as well.
Table 1: Existing Roadway Inventory
Road Name Route
Number
Typical Cross
Section Speed Limit
2021 AADT
(vpd)
US 421 4-lane divided
with a TWLTL 55 mph 11,000
Mid-Atlantic Roofing
Northern Driveway N/A 2-lane
undivided Not Posted 180*
Mid-Atlantic Roofing
Southern Driveway N/A 2-lane
undivided Not Posted 50*
Existing Church
Driveway N/A 2-lane
undivided Not Posted 80*
*AADT based on the traffic counts from 2024 and assuming the PM peak hour was 10% of the AADT.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
U
S
H
W
Y
4
2
1
N
o
r
t
h
Site Location Map
Figure 1
LEGEND
Proposed Site Access
Study Area
N
4
3+
1DS
L
3+
1DS
L
F
20,000 GA
L
DSL
7,000 GAL
DEF
F
20,000 GA
L
RUL12,000 GA
L
DSL
8,000 GAL
PUL
F
F
SITE SUMMARY
SITE NOTES:
DRAWING SCALE
N
US
H
W
Y
4
2
1
N
.
CO
N
C
E
P
T
U
A
L
S
I
T
E
P
L
A
N
6
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
N
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
SPEEDLIMIT55
2024 Existing
Lane Configurations
Figure 3
6
TW
L
T
L
TW
L
T
L
10
0
'
Unsignalized Intersection
Existing Lane
X'Storage (In Feet)
TWLTL Two-Way Left-Turn Lane
SPEEDLIMITXX Posted Speed Limit
LEGEND
TW
L
T
L
TW
L
T
L
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2. 2024 EXISTING PEAK HOUR CONDITIONS
2.1. 2024 Existing Peak Hour Traffic Volumes
Existing peak hour traffic volumes were determined based on traffic counts conducted at
the existing study intersections listed below, in July 2024 by Burns Service Inc. during the
typical weekday AM (7:00 AM – 9:00 AM) and PM (4:00 PM – 6:00 PM) peak periods:
• US 421 and Mid Atlantic Roofing Northern Driveway / Existing Access A
• US 421 and Mid Atlantic Roofing Southern Driveway / Existing Access B
It should be noted that traffic data collection during the summer was approved by NCDOT
during scoping. Traffic volumes were balanced, where appropriate, at the study
intersections. Refer to Figure 4 for 2024 existing weekday AM and PM peak hour traffic
volumes. A copy of the count data is located in Appendix B of this report.
2.2. Analysis of Existing Peak Hour Traffic Conditions
The 2024 existing 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. The results of the analysis are presented in Section 7 of this report.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
N
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
14
/
3
67
0
/
7
0
0
3/
0
1/00/00/5
2024 Existing
Peak Hour Traffic
Figure 4
Note: Based on NCDOT Congestion Management guidelines, a volume of 4 vehicles per hour (vph) was analyzed for
any movement with less than 4 vph.
8
Unsignalized Intersection
Weekday AM / PM Peak
Hour TrafficX / Y
LEGEND
0/
2
86
3
/
6
4
3
0/
1
3/
0
86
3
/
6
6
7
0/
0
0/00/02/15
0/
2
65
9
/
7
0
2
18
/
2
0/20/00/2
1/00/012/5
9 | P a g e
3. 2026 NO-BUILD PEAK HOUR CONDITIONS
In order to account for growth of traffic and subsequent traffic conditions at a future year,
no-build traffic projections are needed. No-build 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. No-build 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 NCDOT and WMPO, it was determined that an annual growth
rate of 1% would be used to generate 2026 no-build weekday AM and PM peak hour traffic
volumes.
3.2. Adjacent Development Traffic
Based on coordination with NCDOT and WMPO, it was determined there were no approved
adjacent developments to consider with this study.
3.3. Future Roadway Improvements
Based on coordination with NCDOT and WMPO, it was determined that there were no
future roadway improvements to consider with this study; however, it should be noted
that a southbound right turn lane, along US 421, is proposed to be constructed at the
Existing Access B by the warehousing development (mentioned in section 1.2 of this
report). Construction of this turn lane is expected to be completed prior to completion of
the proposed site; therefore, this turn lane was analyzed as a background improvement
under 2026 no-build and 2026 build traffic conditions.
3.4. 2026 No-Build Peak Hour Traffic Volumes
The 2026 no-build traffic volumes were determined by projecting the 2024 existing peak
hour traffic to the year 2026. Refer to Figure 5 for an illustration of the 2026 no-build peak
hour traffic volumes at the study intersections.
10 | P a g e
3.5. Analysis of No-Build Peak Hour Traffic Conditions
The 2026 no-build AM and PM peak hour traffic volumes at the study intersections were
analyzed with future geometric roadway conditions and traffic control. The analysis results
are presented in Section 7 of this report.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
N
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
2026 No-Build
Peak Hour Traffic
Figure 5
11
Note: Based on NCDOT Congestion Management guidelines, a volume of 4 vehicles per hour (vph) was analyzed for
any movement with less than 4 vph.
0/
2
88
0
/
6
5
6
0/
1
0/00/02/15
0/
2
67
2
/
7
1
6
18
/
2
0/20/00/2
3/
0
88
0
/
6
8
0
0/
0
1/00/00/5
14
/
3
68
3
/
7
1
4
3/
0
1/00/012/5
Unsignalized Intersection
Weekday AM / PM Peak
Hour TrafficX / Y
LEGEND
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4. SITE TRIP GENERATION AND DISTRIBUTION
4.1. Trip Generation
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, 11th Edition. Table 2 provides a summary of the trip generation potential for the
site.
Table 2: Trip Generation Summary
Land Use
(ITE Code) Intensity
Daily
Traffic
(vpd)
Weekday
AM Peak Hour
Trips (vph)
Weekday
PM Peak Hour
Trips (vph)
Enter Exit Enter Exit
General Office Building
(710) 13,000 sq. ft 198 25 4 5 26
Convenience Store/Gas Station
(945) 19 VFP 4,886 257 257 216 216
Total Trips 5,084 282 261 221 242
*Pass-By Trips:
Convenience Store/Gas Station
(76% AM, 75% PM)
-79 -79 -69 -69
Total Primary Trips 203 182 152 173
*Limited to 10% of the adjacent street traffic.
It should be noted that the proposed convenience store/gas station development and the
office development are to be constructed by different developers and that the 13,000
square foot general office building was only analyzed as part of the trip generation for this
site due the sharing of an access.
It is estimated that the proposed development will generate approximately 5,084 total
site trips on the roadway network during a typical 24-hour weekday period. Of the daily
traffic volume, it is anticipated that 543 trips (282 entering and 261 exiting) will occur
during the weekday AM peak hour and 463 trips (221 entering and 242 exiting) will occur
during the weekday PM peak hour.
Pass-by trips were also 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 trip reductions were limited to 10% of the
adjacent street traffic. Pass-by trips are expected to account for approximately 158 trips
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(79 entering and 79 exiting) during the weekday AM peak hour and approximately 138
trips (69 entering and 69 exiting) during the weekday 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.
The total primary site trips are the calculated site trips after the reduction for pass-by
trips. Primary site trips are expected to account for approximately 385 trips (203 entering
and 182 exiting) during the weekday AM peak hour and 325 trips (152 entering and 173
exiting) during the weekday 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 the primary site trips will be regionally distributed as follows:
• 30% to/from the north via US 421
• 70% to/from the south via US 421
Refer to Figure 6 for an illustration of the site trip distribution percentages and Figure 7
for an illustration of the site trip assignment at the study intersections.
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 8 for the pass-by
site trip distribution. Pass-by site trip assignments are shown in Figure 9.
The total site trips were determined by adding the primary site trips and the pass-by site
trips. Refer to Figure 11 for the total site trip assignment at the study intersections.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
30%
70%
30
%
(1
0
%
)
(5%) (10%)15
%
(2
5
%
)
55
%
15
%
Proposed Site
Trip Distribution
XX%
Entering Trip Distribution
Exiting Trip Distribution
Regional Trip Distribution
Unsignalized Intersection
X%
(Y%)
LEGEND
Figure 6
14
(25%) (60%)
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
Proposed Site
Trip Assignment
Figure 7
30
/
2
2
46
/
4
3
11
2
/
8
4
30
/
2
2
Unsignalized Intersection
Weekday AM / PM Peak
Hour Site TripsX / Y
LEGEND
15
61
/
4
6
18
/
1
7
9/9
18/17
46/43
109/104
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
70
%
/
7
0
%
-7
0
%
/
-
7
0
%
-7
0
%
/
-
7
0
%
Proposed Site
Pass-By
Trip Distribution
Figure 8
16
Unsignalized Intersection
Weekday AM / PM Pass-By
Trip Distribution
X% / Y%
LEGEND
15
%
/
1
5
%
-1
5
%
/
-
1
5
%
15%/15%
15
%
/
1
5
%
-1
5
%
/
-
1
5
%
15%/15%
70%/70%
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
Figure 9
Proposed Site
Pass-By
Trip Assignment
Unsignalized Intersection
Weekday AM / PM Peak
Hour Site Pass-by TripsX / Y
LEGEND
17
12
/
1
0
-1
2
/
-
1
0
12
/
1
0
-1
2
/
-
1
0
55
/
4
9
-5
5
/
-
4
9
-5
5
/
-
4
9
12/10
12/10
55/49
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
Proposed Site
Total
Trip Assignment
Figure 10
18
Unsignalized Intersection
Weekday AM / PM Peak
Hour Site TripsX / Y
LEGEND
42
/
3
2
34
/
3
3
12
4
/
9
4
18
/
1
2
11
6
/
9
5
-5
5
/
-
4
9
-3
7
/
-
3
2
21/19
18/17
58/53
164/153
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5. 2026 BUILD TRAFFIC CONDITIONS
5.1. 2026 Build Peak Hour Traffic Volumes
To estimate traffic conditions with the site fully built-out, the total site trips were added
to the 2026 no-build traffic volumes to determine the 2026 build traffic volumes. Refer to
Figure 11 for an illustration of the 2026 build peak hour traffic volumes with the proposed
site fully developed.
5.2. Analysis of Build Peak Hour Traffic Conditions
Study intersections were analyzed with the 2026 build traffic volumes using the same
methodology previously discussed for existing and no-build 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.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
Figure 10
2026 Build
Peak Hour Traffic
20
Note: Based on NCDOT Congestion Management guidelines, a volume of 4 vehicles per hour (vph) was analyzed for
any movement with less than 4 vph.
13
8
/
9
7
70
1
/
7
2
6
3/
0
1/00/00/5
11
6
/
9
7
82
5
/
6
0
7
0/
1
3/
0
84
3
/
6
4
8
0/
0
0/00/02/15
42
/
3
4
70
6
/
7
4
9
18
/
2
21/210/018/19
Unsignalized Intersection
Weekday AM / PM Peak
Hour TrafficX / Y
LEGEND
59/530/0176/158
21 | P a g e
6. TRAFFIC ANALYSIS PROCEDURE
Study intersections were analyzed using the methodology outlined in the Highway
Capacity Manual (HCM), 6th Edition 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 11.1), was used to complete the analyses for 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 3 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 3: 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
6.1. Adjustments to Analysis Guidelines
Capacity analysis at all study intersections was completed according to the NCDOT
Congestion Management Guidelines.
22 | P a g e
7. CAPACITY ANALYSIS
The following study intersections were analyzed under 2024 existing, 2026 no-build, and
2026 build traffic conditions:
• US 421 and Mid Atlantic Roofing Northern Driveway / Existing Access A
• US 421 and Mid Atlantic Roofing Southern Driveway / Existing Access B
Refer to Tables 4-5 for a summary of capacity analysis results. Refer to Appendices C-D
for the Synchro capacity analysis reports. Refer to Appendix E for the SimTraffic queueing
reports.
23 | P a g e
7.1. US 421 and Mid Atlantic Roofing Northern Driveway / Existing
Access A
Refer to the table below for a summary of the capacity analysis of the subject intersection
during the analysis scenarios.
Table 4: Analysis Summary of US 421 and Mid Atlantic Roofing
Northern Driveway / Existing Access A
Bold denotes improvement and or lane reconfiguration to be done by the developer.
1. Level of service for major-street approach.
2. Level of service for minor-street approach.
Capacity analysis indicates that the major street left turn movements are expected to
operate at LOS B or better during the weekday AM and PM peak hours under all traffic
conditions. The minor street approaches are expected to operate at LOS C during the
weekday AM and PM peak hours under all traffic conditions. It should be noted that 10
95th Max 95th Max
EBLTR --5 34 C 20 C (20)2 3 44 C 17 C (17)2
WBLTR --3 28 C 18 C (18)2 8 46 C 19 C (19)2
NBL 100 0 24 B 10 0 18 A 9
NBT (2)------------------
NBR 100 ----------------
SBL 100 0 8 A 9 0 9 A 9
SBT ------------------
SBTR ------------------
EBLTR --5 38 C 20 C (20)2 3 38 C 17 C (17)2
WBLTR --3 28 C 18 C (18)2 8 50 C 19 C (19)2
NBL 100 0 24 B 10 0 18 A 9
NBT (2)------------------
NBR 100 ----------------
SBL 100 0 7 A 9 0 9 A 9
SBT ------------------
SBTR ------------------
EBLTR --15 93 C 22 C (22)2 13 72 C 17 C (17)2
WBLTR --5 58 C 21 C (21)2 10 54 C 22 C (22)2
NBL 100 5 50 B 11 3 34 A 10
NBT (2)----9 ------------
NBR 100 ----------------
SBL 100 0 4 A 9 0 12 A 10
SBT (2)------------------
SBR 100 ----------------
Existing
Storage
(ft)
LANE
GROUP
ANALYSIS
SCENARIO Overall
LOS
(sec)
Approach
LOS
(sec)
Delay
(sec)
Lane
LOS
Overall
LOS
(sec)
Approach
LOS
(sec)
Delay
(sec)
Lane
LOS
Weekday AM Peak Hour
2026
Build N/A N/AB (11)1
A (9)1
A (10)1
A (10)1
2026
No-Build N/A N/AB (10)1
A (9)1
A (9)1
A (9)1
Weekday PM Peak Hour
Queue (ft)Queue (ft)
N/A2024
Existing N/AB (10)1
A (9)1
A (9)1
A (9)1
24 | P a g e
seconds of delay was reported in the table above as LOS A and LOS B due to rounding as
10 seconds is the threshold between LOS B and LOS C for a signalized intersection.
SimTraffic queuing reports indicate that maximum queues are expected to spill back
approximately 95 on the minor street approach during the peak hours under 2026 build
traffic conditions These queues are not expected to block entering traffic from turning into
the site and making a left to go to the convenience store and gas pumps.
A right turn lane was considered based on the NCDOT Policy on Street and Driveway
Access to North Carolina Highways. A southbound right turn lane on US 421 is warranted
at the Existing Access A under 2026 build traffic conditions. Due to the existing northbound
TWLTL, left turn lane warrants were not considered. The following improvements are
recommended by the developer:
• Construct a southbound right turn lane on US 421 with 100 feet of storage and
appropriate taper length.
• Modify the striping of the existing northbound US 421 two-way left-turn lane
(TWLTL), if necessary.
25 | P a g e
7.2. US 421 and Mid Atlantic Roofing Southern Driveway / Existing
Access B
Refer to the table below for a summary of the capacity analysis of the subject intersection
during the analysis scenarios.
Table 5: Analysis Summary of US 421 and Mid Atlantic Roofing
Southern Driveway / Existing Access B
Underline denotes improvement and or lane reconfiguration to be done by Others.
1. Level of service for major-street approach.
2. Level of service for minor-street approach.
95th Max 95th Max
EBLTR --5 39 C 17 C (17)2 3 40 C 17 C (17)2
WBLTR --5 43 C 19 C (19)2 3 31 C 17 C (17)2
NBL 100 3 32 B 10 0 24 A 9
NBT ------------------
NBTR ------------------
SBL 100 0 25 A 9 0 15 A 9
SBT --------------
SBTR ------------------
EBLTR --5 39 C 17 C (17)2 3 38 C 17 C (17)2
WBLTR --5 43 C 19 C (19)2 5 49 C 18 C (18)2
NBL 100 3 36 B 10 0 24 A 9
NBT ------------------
NBTR ------------------
SBL 100 0 10 A 9 0 24 A 9
SBT (2)--------------
SBR FULL ----------------
EBLTR --193 418 F 60 F (60)2 93 228 D 26 D (26)2
WBLTR --8 48 D 32 D (32)2 5 35 C 24 C (24)2
NBL 100 20 87 B 11 10 62 A 10
NBT ----14 ------------
NBTR ------------------
SBL 100 0 21 A 9 0 16 A 10
SBT (2)------------------
SBR FULL ----------------
A (9)1
N/A N/AB (10)1 A (9)1
A (9)1
A (9)1
2024
Existing N/AB (10)1
2026
No-Build
N/A
A (9)1 A (10)1
B (11)1 A (10)12026
Build N/A
Lane
LOS
Delay
(sec)
Approach
LOS
(sec)
Overall
LOS
(sec)
Queue (ft)Lane
LOS
A (9)1
N/AA (9)1
ANALYSIS
SCENARIO
LANE
GROUP
Existing
Storage
(ft)
Weekday AM Peak Hour Weekday PM Peak Hour
Queue (ft)Delay
(sec)
Approach
LOS
(sec)
Overall
LOS
(sec)
26 | P a g e
Table 5: Analysis Summary of US 421 and Mid Atlantic Roofing
Southern Driveway / Existing Access B - Continued
Bold denotes improvement and or lane reconfiguration to be done by the Developer.
Underline denotes improvement and or lane reconfiguration to be done by Others.
1. Level of service for major-street approach.
2. Level of service for minor-street approach.
Capacity analysis indicates that the westbound minor street approach is expected to be
impacted and degrade from LOS C during the weekday AM peak hour under 2026 no-build
traffic conditions to a LOS D during the weekday AM peak hour under 2026 build traffic
conditions. While the westbound approach is expected to be impacted, the approach is
expected to operate acceptably, and queues are not expected to exceed 50 feet during
the peak hours under 2026 build traffic conditions. The eastbound minor street approach
is expected to operate at LOS F during the weekday AM peak hour and LOS D during the
weekday PM peak hour under 2026 build traffic conditions with maximum queues
exceeding 415 feet during the peak hours.
Due to the operational and queuing impacts, the eastbound approach was also analyzed
with two egress lanes under 2026 build – improved traffic conditions. Under 2026 build –
improved traffic conditions, the eastbound approach is expected to operate at LOS D
during the weekday AM peak hour and operate at LOS C during the weekday PM peak
hour. Maximum queues are not expected to exceed 175 feet during the peak hours under
2026 build – improved traffic conditions. While queues are still expected to spill back past
the convenience store entrance, SimTraffic queuing reports show average queues of less
than 55 feet are expected, which indicates that longer spillbacks are not anticipated to be
the norm.
95th Max 95th Max
EBL 125 53 130 F 52 28 80 D 30
EBTR --48 173 C 17 33 100 B 14
WBLTR --8 61 D 32 D (32)2 5 44 C 24 C (24)2
NBL 100 20 84 B 11 10 67 A 10
NBT ------------------
NBTR ------------------
SBL 100 0 20 A 9 0 26 A 10
SBT (2)------------6 ----
SBR FULL ----------------
B (11)1 A (10)1N/A
2026
Build -
Improved
N/A
C (18)2D (25)2
A (9)1 A (10)1
Lane
LOS
Delay
(sec)
Approach
LOS
(sec)
Overall
LOS
(sec)
Queue (ft)Lane
LOS
ANALYSIS
SCENARIO
LANE
GROUP
Existing
Storage
(ft)
Weekday AM Peak Hour Weekday PM Peak Hour
Queue (ft)Delay
(sec)
Approach
LOS
(sec)
Overall
LOS
(sec)
27 | P a g e
No turn lanes were warranted based on the NCDOT Policy on Street and Driveway Access
to North Carolina Highways. Additionally, due to the construction of a southbound right
turn lane by the warehousing development, and the existing northbound TWLTL, right and
left turn lane warrants were not considered. The following improvements are
recommended by the developer:
• Construct an eastbound left turn lane on the Existing Access B that provides a
minimum of 125 feet of left turn stacking for the egress of Access B.
• Modify the striping of the existing two-way left-turn lane (TWLTL) on US 421,
if necessary.
28 | P a g e
8. CONCLUSIONS
This Traffic Impact Analysis was conducted to determine the potential traffic impacts for
the proposed Highway 421 C-Store to be located at 3705 N US Highway 421 in New
Hanover County, North Carolina. The proposed development, anticipated to be completed
in 2026, is assumed to consist of a 19-vehicle fueling position (VFP) convenience store/gas
station. A 13,000 square foot general office building was also analyzed as part of the trip
generation for the proposed site due to the two developments sharing an access. It should
be noted that the proposed convenience store/gas station development and the office
development are to be constructed by different developers.
Site access is proposed via two (2), existing, full movement driveways on US 421. Both
driveways are (are proposed to be) aligned with the Mid-Atlantic Roofing Supply Driveways
located on the opposite side of US 421. Construction of the southernmost existing access
(Access B) was completed by the recent warehousing development that is located behind
the proposed convenience store/gas station.
The study analyzes traffic conditions during the weekday AM and PM peak hours for the
following scenarios:
• 2024 Existing Traffic Conditions
• 2026 No-Build Traffic Conditions
• 2026 Build Traffic Conditions
Trip Generation
The total primary site trips are the calculated site trips after the reduction for pass-by
trips. Primary site trips are expected to account for approximately 385 trips (203 entering
and 182 exiting) during the weekday AM peak hour and 325 trips (152 entering and 173
exiting) during the weekday PM peak hour.
Adjustments to Analysis Guidelines
Capacity analysis at all study intersections was completed according to 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.
29 | P a g e
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 12 for an illustration
of the recommended lane configuration for the proposed development.
2026 Recommended Improvements by Developer
US 421 and Mid Atlantic Roofing Northern Driveway / Existing Church
Driveway
• Construct a southbound right turn lane on US 421 with 100 feet of storage and
appropriate taper length.
• Modify the striping of the existing northbound US 421 two-way left-turn lane
(TWLTL), if necessary.
US 421 and Mid Atlantic Roofing Southern Driveway / Access B
• Construct an eastbound left turn lane on the Existing Access B that provides a
minimum of 125 feet of left turn stacking for the egress of Access B.
• Modify the striping of the existing two-way left-turn lane (TWLTL) on US 421,
if necessary.
US 421 C-Store
New Hanover County, NC
Scale: Not to Scale
SI
T
E
NN
Mid Atlantic Roofing
Northern Driveway
Existing Access
A
421
Mid Atlantic Roofing
Southern Driveway
Existing Access
B
*Modify the striping of the existing TWLTL, if
necesarry.
*
LEGEND
Unsignalized Intersection
Existing Lane
X'Storage (In Feet)
Improvements by Developer
10
0
'
Figure 12
2026 Recommended
Lane Configurations
30
TW
L
T
L
TW
L
T
L
TW
L
T
L
10
0
'
TW
L
T
L
*
125'
DR
O
P
L
A
N
E
Improvements by Others