CC - Traffic Impact Study (draft)Thompson Engineers
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Traffic Inc.
Table of Contents
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
EXECUTIVE SUMMARY..........................................................................................................................1
Introduction..............................................................................................................................................
1
ProposedDevelopment.............................................................................................................................
l
StudyArea................................................................................................................................................1
Conclusions..............................................................................................................................................
1
INTRODUCTION........................................................................................................................................
3
PROPOSED DEVELOPMENT....................................................................................................................
3
STUDY AREA CONDITIONS....................................................................................................................
5
StudyArea................................................................................................................................................
5
LandUse...................................................................................................................................................
5
STUDYPERIOD..........................................................................................................................................
5
BuildOut Year..........................................................................................................................................
5
StudyHours..............................................................................................................................................
5
EXISTING CONDITIONS...........................................................................................................................5
RoadSystem.............................................................................................................................................5
TrafficVolumes........................................................................................................................................5
DailyTraffic.............................................................................................................................................
7
AccidentAnalysis.....................................................................................................................................
7
SystemImprovements..............................................................................................................................
7
PROJECTEDTRAFFIC...............................................................................................................................
8
BackgroundTraffic...................................................................................................................................
8
OffSite Traffic.........................................................................................................................................
8
TripGeneration.......................................................................................................................................
10
TripDistribution.....................................................................................................................................
l l
SiteTraffic..............................................................................................................................................
l 1
TotalTraffic............................................................................................................................................
l l
TRAFFICANALYSIS...............................................................................................................................14
Capacity Analysis and Level of Service.................................................................................................14
IntersectionAnalysis..............................................................................................................................15
Required Improvements Due to Existing Traffic Conditions.............................................................15
Required Improvements Due to 2020 Background Traffic Conditions .............................................
15
Required Due to 2020 Total Traffic Conditions................................................................................
16
RoadwayAnalysis..................................................................................................................................16
SiteAccess..............................................................................................................................................16
SiteCirculation.......................................................................................................................................17
TurnLanes..............................................................................................................................................18
CONCLUSIONS.........................................................................................................................................18
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List of Figures
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Figure1 - Project Location........................................................................................................................... 3
Figure2 - Preliminary Site Plan....................................................................................................................
4
Figure 3 - Existing AM Peak Hour Conditions.............................................................................................
6
Figure 4 - Existing PM Peak Hour Conditions.............................................................................................
6
Figure 5 — 2020 Build Out Year AM Peak Hour Background Traffic..........................................................
8
Figure 6 — 2020 Build Out Year PM Peak Hour Background Traffic..........................................................
9
Figure7 - Trip Distribution.........................................................................................................................
11
Figure 8 - AM Peak Hour Site Traffic........................................................................................................
12
Figure 9 - PM Peak Hour Site Traffic.........................................................................................................
12
Figure 10 — 2020 Build Out Year Total AM Peak Hour Traffic.................................................................13
Figure 11- 2020 Build OUt Year Total PM Peak Hour Traffic..................................................................
13
Figure 12 - Internal Daily Traffic Volumes................................................................................................17
Figure 13 - Right Turn Lane Guidelines for Four Lane Road....................................................................18
List of Tables
Table 1 — 2018 Existing Traffic.................................................................................................................... 7
Table 2 — Accident Data for Ustick Road and Venable Lane Intersection (2012-2016) ..............................
7
Table 4 - Trip Generation Summary...........................................................................................................
10
Table 5 — AM Peak Hour Intersection Capacity Analysis Summary..........................................................14
Table 6 — PM Peak Hour Intersection Capacity Analysis Summary.........................................................
15
Table7 - Roadway Segment ADT..............................................................................................................
16
Table 8 - Right Turn Lane Data..................................................................................................................18
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Thompson Engineers
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EXECUTIVE SUMMARY
Introduction
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Thompson Engineers, Inc. has been retained to prepare a traffic impact study for the
proposed Summertown Development in Meridian, Idaho. The project is located on Ustick
Road west of Meridian Road. The purpose of this study is to evaluate the potential traffic
impacts resulting from the current site plan and make recommendations for mitigation of
those impacts. The study is prepared in accordance with the requirements of the Ada
County Highway District (ACHD) Policy, Section 7106 — Traffic Impact Studies.
Proposed Development
The project is a residential development of approximately 9 single family dwelling units
and 272 apartments. The development will be constructed in one phase with an expected
2020 build out year.
The site is expected to access the transportation system primarily via Ustick Road via
Venable Lane. The site is also expected to have connectivity to Meridian Road via
Ridgebury Avenue and Indian Rocks Street.
The site is located within the Meridian City Limits.
Study Area
The area of influence is anticipated to be Ada County, Idaho, including the City of
Meridian. The primary impacts will be along Ustick Road, Venable Lane, and Indian
Rocks Street. The study area will include the intersections of:
■ Venable Lane and Ustick Road
■ Meridian Road and Indian Rock Street
Conclusions
Below are the findings of this report:
■ Based on the trip generation methods recommended in the Trip Generation Manual,
the site will generate 2,076 trips per day, of which 132 trips will occur during the
AM peak hour and 161 trips will occur during the PM peak hour.
■ Ustick Road was recently widened from two lanes to five lanes, and included curb,
gutter and sidewalk.
■ The intersection of Ustick Road and Venable Lane will operate at LOS C under
background traffic conditions in the build out year. The southbound approach will
operate at LOS C and will have a v/c of 0.38.
■ The intersection of Ustick Road and Venable Lane will operate at LOS D under total
traffic conditions in the build out year. The southbound approach will operate at
LOS D and will have a v/c of 0.49.
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Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
E The intersection of Meridian Road and Indian Rocks Street will operate at LOS B
under background traffic conditions, and LOS B under total traffic conditions in the
build out year. The critical peak hour is in the PM peak hour.
■ Traffic from the subdivision to the west will divert to Venable Lane when Venable
Lane is improved and the barriers to the two approaches are removed. This traffic
will not be diverted until the road is improved by this development, therefore will
only affect total traffic conditions.
■ The three access points on Venable Lane will operate at acceptable levels of service
under total traffic conditions.
■ Venable Lane will operate at better than level of service D under total traffic
conditions, which is acceptable for a collector road.
■ The site will impact Ridgebury Avenue and Indian Rocks Street, local roads. Under
total traffic conditions, the total volume on these roads is anticipated to be less than
1,000 vehicles per day.
■ All internal roads will carry less than 1,000 vehicles per day under total traffic
conditions.
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Thompson Engineers
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INTRODUCTION
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Thompson Engineers, Inc. has been retained to prepare a traffic impact study for the
proposed Summertown Development in Meridian, Idaho. The project is located on
Ustick Road west of Meridian Road, approximately as shown in Figure 1. The
purpose of this study is to evaluate the potential traffic impacts resulting from the
project and make recommendations for mitigation of those impacts. In particular,
the scope of the study includes the following:
Trip generation of the proposed development
Trip distribution and traffic assignment of the site generated traffic
The capacity of the transportation system to support the development
Figure I - Proiect Location
r Ustick Rd
W Lowrry St
VV Claire Or W Claire Sf
Tune Creek Or kL
C
ro
6
7
� Project
� Location
Q
W Stanhope St
w
z
Settlers Park Cassidy Dr � p`
Settlers Park N Curt
b9
E Ustick Rd ,
z
E Addeson St
E Baldwin St
W Claire St
W Indian Rocks St
r� Tulley Park 10 �V Woodbury Dr
2p h i%r
Tultey Park W Waterbury Dr
°Five We Creek
ear Dr W Chateau Ave 8th Meridian W C!>ns <`�a Or
Street
Pefk 66h Street
W Tana Dr -'�4 f)ehrlar Dr 4'Park
W -"anrlawood Or
u�
Q
r Cherry Ln z
Z
C�
E Ham
ryIbllr l
E W°
E Blue Heron St
E
W Willowbro k DE James Gourd Dr
0
r
m
L
J A a
z �I� CVAs --
PROPOSED DEVELOPMENT
,mel Dr
E
Lynn Dr
C
E 'Fairview AVe
The project is a residential development of approximately 9 single family dwellings and
272 apartments. A preliminary site plan is shown in Figure 2. The site is expected to
access the transportation system via Venable Lane to Ustick Road, with a secondary
access to Meridian Road via Ridgebury Avenue and Indian Rocks Street.
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Figure 2 - Preliminary Site Plan
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Ustick Road
!Milo i TI. -1*111U1 (7 TTI'111=1
North-Entira ce4
\,J F TAT
— vvrangFer moaa
":I -C'.10 :oY
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STUDY AREA CONDITIONS
Study Area
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
The area of influence is anticipated to be Ada County, Idaho, including the City of
Meridian. The primary impacts will be along Ustick Road, Venable Lane, and Indian
Rocks Street. The study area will include the intersections of Ustick Road and Venable
Lane, and Indian Rocks Street and Meridian Road as determined by a special model run
of the COMPASS transportation model and verified by ACHD. The future
intersections of Venable Lane and Wrangle Street, and Ridgebury Avenue and
Wrangler Street are also included in the study.
Land Use
The site is within the Meridian City limit and is currently vacant. Existing zoning is for
residential use.
STUDY PERIOD
Build Out Year
The build out year for this project is assumed to be 2020 to correspond with COMPASS
data,. Actual build out of the site will depend on market conditions and project
implementation.
Study Hours
The AM peak hour, between 7:00 AM and 9:00 AM, and the PM peak hour, between
4:00 PM and 6:00 PM, were the study hours of this report.
EXISTING CONDITIONS
Road System
Ustick Road is classified as a principal arterial by ACHD. In the vicinity of this project, it
has two through lanes in each direction and a center two way left turn lane with an urban
section. There is a posted speed of 40 MPH in front of the project.
Venable Lane is a gravel road. It is proposed as a two lane collector street.
Indian Rocks Street is a local street with an urban section.
The intersection of Ustick Road and Venable Lane is stop controlled with Ustick Road as
the major, uncontrolled street.
The intersection of Meridian Road and Indian Rocks Street is stop controlled with
Meridian Road as the major, uncontrolled street.
Traffic Volumes
AM and PM peak hours traffic counts were obtained at the intersections in the study area
the week of January 31, 2018. Existing AM peak hour traffic volumes are shown in
Figure 3. Existing PM peak hour traffic volumes are shown in Figure 4.
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Figure 3 - Existing AM Peak Hour Conditions
SII
V Ustick Rjd, 79 0 81
46
780
0
0 0 1
3 0
V—S—tarjh?P-e--$t--.
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
.... ... .... Uskk Pd
3 756 0
0 0
23
9 380 0
it
Figure 4 - Existing PM Peak Hour Conditions
V UsNck Rjd,
'0 61 1 34
a
0�
447 L*
0
1 0 1
5 2
V tanh4
2 19!
�93
�=798
7
8 517 0
4
3 C#�D 4
0 => ao
14 � 0
40 851 0
E Ustic . R.d
I........._........_
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Daily Traffic
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Daily counts on the study roadway segments were obtained by L2 Data Collection
between January 31 and February 1, 2018 are summarized in Table 1.
Table I — 2018 Existing Traffic
Accident Analysis
Accident data for the years 2012 through 2016 was obtained from LHTAC. The full
crash data report is included in the appendix of this report.
There were three reported accidents on Indian Rocks Street. None of the accidents listed
roadway conditions a contributing cause. A statistical analysis of these accidents is not
relevant.
There were 15 accidents in the vicinity of the intersection of Ustick Road and Venable
Lane. Only 8 were classified as intersection related. The data is summarized in Table 2.
The full crash data report is included in the appendix
Table 2 — Accident Data for Ustick Road and Venable Lane Intersection (2012-2016)
Fatal Accidents 0
Injury Accidents 1
Property Damage Accidents 7
Total Accidents 8
Contributing factors for all 15 accidents varied considerably but the most common
contributing factor was inattention by the driver or failure to yield or obey the traffic
signal. No roadway conditions or visual obstructions were described as contributing
factors. Ustick Road was recently constructed from 2 lanes to 5 lanes, so the accident
data is not relevant to the current facilities.
System Improvements
ACHD has a project to widen Meridian Road to five lanes in the five year work plan.
This development will be required to construct Venable Lane as a collector road. This
improvement could alter traffic patterns from the development to the west.
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PROJECTED TRAFFIC
Background Traffic
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Future traffic is obtained by expanding the existing traffic volumes by a growth factor.
A growth factor of 3.0% per year is used for this study based on past records.
Background AM and PM Peak Hour traffic for the 2020 build out year is shown in
Figure 5 and Figure 6. Traffic on Indian Rocks Street is not increased because this area
is built out and not subject to growth.
Off Site Traffic
The development to the west is partially built out. When Venable Lane is constructed,
some traffic from this development will divert to Venable Lane. This traffic will not be
added to the background traffic but will be added to the total traffic.
Figure S — 2020 Build Out Year AH Peak Hour Background Traffic
N �st4It R�:I
86 D 89 ------
852 356 �4
D 1
3 826 D
3 D of
8 D `s
M1! 5ian_hgp5t.� ♦— 23 � 0
D
0 0, ..
---------------
% SI
. ... ... ... >
a$
4
Z
a
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Traffic Impact Study
Thompson Engineers Summertown Subdivision, Meridian, Idaho
Traffic and Crvrl Inc.
Figure 6 — 2020 Build Out Year PM Peak Hour Background Traffic
w�
!V Ustick Rd 6 [
'€u 69 1 3$
90 � A 1D5
503 <�= 898
0 8 �.
'7lJ LJ Lf1"
5' 8 582 D
�
6 fl2 3 � D
N tanh4RSt t� ^ s` D D
�j ---- 14 D
f
40 958 D
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Trip Generation
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
In the absence of site-specific data, site trip generation is estimated using the procedures
recommended in the latest edition of the Trip Generation Manual (10"' edition), published
by the Institute of Transportation Engineers. Site trip generation is obtained by applying
the average trip generation rates obtained from the Manual for each category of land use
within the development. Table 4 shows the trip generation of the site.
Table 3 - Trip Generation Summary
Summary of Trip Generation
Average Weekday Driveway Volumes
ITE
24 hr 2 -Way
Enter
Exit
Land Use
No.
Units
Total
Rate I
Total
Code
Rate
Total
Rate
Single Family
Code
Total
210
Total
9
DU
9.44
85
85
Dwellings
210
Low Rise
DU
0.19
2
2
0.56
220
5
272
DU
7.32
1991
1991
Apartments
Total
Low Rise
2,076
2,076
Average Weekday AM Peak Hour Driveway Volumes
ITE
Enter
Enter
Exit
Exit
Land Use
No.
Units
Rate
Total
Rate
Total
Code
Total
Total
Total
Single Family
210
9
DU
0.19
2
2
0.56
5
5
7
Dwellings
Low Rise
220
220
272
DU
0.11
29
29 0.35
96
96
125
56
Apartments
Apartments
Total
31
31
101
101
132
Average Weekday PM Peak Hour Driveway Volumes
ITE
Enter
Enter
Exit
Exit
Land Use
No.
Units
Rate
I Total
Rate
Total
Code
I Total
Total
Total
Single Family
210
9
DU
0.62
6
6
0.37
3
3
9
Dwellings
Low Rise
220
272
DU
0.35
96
96
0.21
56
56
152
Apartments
Total
102
102
59
59
161
All trips are anticipated to be by single occupancy vehicle. There is no reduction for trips
due to modal split or pass -by trips. No trips will be retained on site as captured trips.
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Trip Distribution
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
In order to determine impacts, the trips generated by the site must be distributed to
destinations throughout Ada County and assigned to the transportation system. The
distribution for this development is based on information obtained from COMPASS. Site
traffic distribution for the development is shown in Figure 7.
Figure 7 - Trip Distribution
M1I--.__--------Qr - __ ...... .. ... ....._... E �*ickR.
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� � � u uw l ulnuuL
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n
f h�1Cin,. P "� .:curl uu r r�rmJrn�luurrnrru% -_l ,
---
-:
A r
c
Site Traffic
Site traffic is distributed at the study intersections in accordance with the distribution
from Figure 7. Figure 8 shows the distribution of site generated traffic for AM peak hour
traffic conditions. Figure 9 shows the distribution of site generated traffic for PM peak
hour traffic conditions.
Total Traffic
The site traffic is then added to the background traffic as determined above. Figure 10
shows the total traffic at each intersection for AM peak hour conditions. Figure 11 shows
the total traffic at each intersection for PM peak hour conditions.
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Traffic Impact Study
Thompson Engineers Summertown Subdivision, Meridian, Idaho
Traffic and Civii tnc.
Figure 8 - AM Peak Hour Site Traffic
D. D .....D .._.
N Ustick Rd
15 8 � ' in
DD
435 �► t D D
D t���1 S 15
51 0
4
5 10 25 D 61 d
�41
�D
10 D
1 � i
D 10 D
D 5
1 ... ...rD� �D
��1D 5 J 1
��D 5
D D y' — D 3 5
- . i
Figure 9 - PM Peak Hour Site Traffic
45 42
425
25 D
D 10 D
D �D o
15 � �=D �
a D D
D 10 D
��a a
0
ao
15 D D
r,r .
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Thompson Engineers Summertown Subdivision, Meridian, Idaho
Traffic and Civil Traffic Impact Study
Inc.
Figure 10 — 2020 Build Out Year Total AM Peak Hour Traffic
...
86 D 89 1
31 8��—
InI r5dt'�Fw� wm"sr gym"_"'
35
87 D
21 10
46 D
8521*
8 �� � cr-
3D D 92
18 5
36
1D
Figure H- 2020 Build OUt Year Total PM Peak Hour Traffic
3 836 D
o 38 � o 0
17 415 D
69 1 38
----
84 42
iami`mow � � _....._._....
25
52 D
_Fa$_ Carie at
49 35
34 D
2 10
5
D
a+
f
Q
l
9.
90
5031=
25
21 D 56
36 12
27
7
1D5
898
100
l 8 592 D
3�� D 0
D a D23 0
5
55 958 D
1
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TRAFFIC ANALYSIS
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Capacity Analysis and Level of Service
Capacity analysis was performed using the Highway Capacity Software (HCS2010),
based on the 2010 edition of the Highway Capacity Manual. Level of service for
intersections is based on the average delay of vehicles traveling through the intersection.
Table 5 shows the AM peak hour intersection capacity analysis results. Table 6 shows
the PM peals intersection capacity analysis results. Copies of the calculations are
included in the appendix of this report.
Table 4 - AH Peak Hour Intersection Capacity Analysis Summary
LOS Summary
2018
2020 Build Out Year
Existing
Background
Total
Delay
Delay
Delay
AM Peak Hour Conditions
s/v
v/c
LOS
s/v
v/c
LOS
s/v
v/c
LOS
Ustick/Venable
15.7
C
17.6
C
22.5
C
NB Approach
11.1
0.00
B
11.4
0.00
B
19.1
0.34
C
SB Approach
15.7
0.33
C
17.6
0.40
C
22.5
0.48
C
EB Approach
8.1
0.04
A
8.3
0.05
A
8.3
0.05
A
WB Approach
9.4
0.00
A
9.7
0.00
A
10.0
0.04
A
Meridian/Indian Rock
16.4
C
17.7
C
18.5
C
NB Approach
9.6
0.01
A
9.9
0.01
A
10.0
0.03
A
EB Approach
16.4
0.10
C
17.7
0.11
C
18.5
0.16
C
Wagner/Ridgebury
9.2
A
NB Approach
8.7
0.01
A
SB Approach
9.2
0.01
A
EB Approach
7.2
0.00
A
WB Approach
7.2
0.00
A
Wagner/Venable
8.6
A
WB Approach
8.6
0.01
A
SB Approach
7.2
0.00
A
North Venable Approach
9.5
A
WB Approach
9.5
0.04
A
SB Approach
7.4
0.01
A
South Venable Approach
9.2
A
WB Approach
9.2
0.05
A
SB Approach
7.3
0.01
A
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Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Table 5 - PM Peak Hour Intersection Capacity Analysis Summary
LOS Summary
2018
2020 Build Out Year
Existing
Background
Total
Delay
Delay
Delay
AM Peak Hour Conditions
s/v
v/c
LOS
s/v
v/c
LOS
s/v
v/c
LOS
Ustick/Venable
19.6
C
24.1
C
34.4
D
NB Approach
14.7
0.01
B
16.4
0.01
C
18.4
0.23
C
SB Approach
19.6
0.29
C
24.1
0.38
C
34.4
0.49
D
EB Approach
10.5
0.11
B
11.4
0.14
B
11.4
0.14
B
WB Approach
8.3
0.01
A
8.5
0.01
A
8.9
0.10
A
Meridian/Indian Rock
13.6
B
14.7
B
14.5
B
NB Approach
8.8
0.04
A
9.0
0.05
A
9.2
0.07
A
EB Approach
13.6
0.04
B
14.7
0.05
B
14.5
0.07
B
Wagner/Ridgebury
9.2
A
NB Approach
8.7
0.02
A
SB Approach
9.2
0.01
A
EB Approach
7.2
0.00
A
WB Approach
7.2
0.00
A
Wagner/Venable
8.7
A
WB Approach
8.7
0.01
A
SB Approach
6.1
0.01
A
North Venable Approach
10.1
B
WB Approach
10.1
0.07
B
SB Approach
7.3
0.03
A
South Venable Approach
9.6
A
WB Approach
9.6
0.03
A
SB Approach
7.4
0.02
A
Intersection Analysis
Required Improvements Due to Existing Traffic Conditions
The intersection of Ustick Road and Venable Lane operates at an acceptable level of
service under existing AM and PM traffic conditions. The volume to capacity ratio on all
lane groups is below 0.90. No improvements are required to mitigate existing traffic
conditions.
The intersection of Meridian Road and Indian Rocks Street operates at an acceptable
level of service under existing AM and PM traffic conditions. The volume to capacity
ratio on all lane groups is below 0.90. No improvements are required to mitigate existing
traffic conditions.
Required Improvements Due to 2020 Background Traffic Conditions
The intersection of Ustick Road and Venable Lane is anticipated operate at an acceptable
level of service under background AM and PM traffic conditions. The volume to
capacity ratio on all lane groups is anticipated to be below 0.90. No improvements are
required to mitigate background traffic conditions.
The intersection of Meridian Road and Indian Rocks Street is anticipated to operate at an
acceptable level of service under background AM and PM traffic conditions. The volume
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Thompson Engineers
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Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
to capacity ratio on all lane groups is anticipated to be below 0.90. No improvements are
required to mitigate background traffic conditions.
Required Due to 2020 Total Traffic Conditions
The intersection of Ustick Road and Venable Lane is anticipated operate at an acceptable
level of service under total AM and PM traffic conditions. The volume to capacity ratio
on all lane groups is anticipated to be below 0.90. No improvements are required to
mitigate total traffic conditions.
The intersection of Meridian Road and Indian Rocks Street is anticipated to operate at an
acceptable level of service under total AM and PM traffic conditions. The volume to
capacity ratio on all lane groups is anticipated to be below 0.90. No improvements are
required to mitigate total traffic conditions.
Roadway Analysis
Roadway segments are analyzed under build out year peak hour traffic in accordance
with the ACHD Development Policy Manual. Local roads are assessed using the daily
volume of traffic. Results are shown in Table 7.
Table 6 - Roadway Segment ADT
Roadway Segment
Location
Existing
Traffic
Off Site
Traffic
Site
Traffic
Total
Traffic
North of
Ridgebury Ave
Indian Rock
56
0
315
371
East of
Indian Rock St
Ridgebury
393
0
315
708
The maximum allowable daily traffic on a local road is 2,000 vehicles per day. The total
traffic on Ridgebury Avenue and Indian Rock Street will fall well below the allowable
threshold.
Collector roads are assessed based on the peak hour directional volume. The maximum
peak hour directional volume allowed on a collector road, according to Table 2 in Section
7100 of the Development Policy Manual, is 425 vehicles per hour. In review of Figures
10 and 11, the maximum anticipated directional volume will be 125 vehicles per hour.
Site Access
All site accesses are anticipated to operate at an acceptable level of service. The
developer is proposing three access points on Venable Lane. The ACHD Development
Policy Manual requires driveways on collector roads be separated by 245 feet for a 25
mph posted speed. As shown in Figure 12, the two southerly driveways meet this spacing
requirement. The north driveway is located between Ustick Road and a driveway for the
apartments to the west. This spacing does not meet policy and will require an exception.
The south driveway is offset from Stanhope Street by about 100 feet. This approach will
require an exception. The volume on both of these streets will be very low and will
remain very low, so an exception to policy may be allowed.
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Thompson Engineers Summertown Subdivision, Meridian, Idaho
Trak and Civil Traffic Impact Study
Inc.
Site Circulation
Anticipate internal daily traffic volumes are shown in Figure 12. None of the internal
roadways are expected to exceed 1,000 vehicles per day.
Figure 12 - Internal Daily Traffic Volumes
T —JUT-Vpu
J -ELI
0 U O C
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ThompsonEngineers
Traffic and Civil Inc.
Turn Lanes
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
Right turn lanes are analyzed using the guidelines in the ACHD Development Policy
Manual.
Table 7 - Right Turn Lane Data
Roadway
Intersection
Variable
Through
Traffic
Right
Turns
Critical
Movement
Ustick Road
Venable
AM Peak
860
8
PM Peak
528
25
X
Figure 13 - Right Turn Lane Guidelines for Four Lane Road
INPUT
Roadway geometry:
4 -lane roadway
Variable
Value
Major -road speed, mph:
50
Major -road volume (one direction), \sh/h:
528
Right -turn volume, \eh/h:
25
f67Ii71ili
Variable
Value
Limiting right -tum volume, voh/h:
49
Guidance for determining the need for a major -road
right -turn bay for a 4 -lane roadway:
Do NOT add right -turn bay.
Based on the posted speed limit, a right turn lane is not warranted for the eastbound right
turn movement on Ustick Road at Venable Lane.
There is an existing two way center left turn lane in Ustick Road. A left turn lane
analysis is not required.
CONCLUSIONS
This study identifies transportation impacts associated with the proposed Summertown
Development in Meridian Idaho. The project is a single and multi family development.
Below are the findings of this report:
■ Based on the trip generation methods recommended in the Trip Generation Manual,
the site will generate 2,076 trips per day, of which 132 trips will occur during the
AM peak hour and 161 trips will occur during the PM peak hour.
■ Ustick Road was recently widened from two lanes to five lanes, and included curb,
gutter and sidewalk.
S.•Iprojectsl18-08 Summertownldocs&mmertown TIS.docx Page 18
Thompson Engineers
Traffic and Civil Jnc.
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
E The intersection of Ustick Road and Venable Lane will operate at LOS C under
background traffic conditions in the build out year. The southbound approach will
operate at LOS C and will have a We of 0.38.
■ The intersection of Ustick Road and Venable Lane will operate at LOS D under total
traffic conditions in the build out year. The southbound approach will operate at
LOS D and will have a v/c of 0.49.
■' The intersection of Meridian Road and Indian Rocks Street will operate at LOS B
under background traffic conditions, and LOS B under total traffic conditions in the
build out year. The critical peak hour is in the PM peak hour.
■ Traffic from the subdivision to the west will divert to Venable Lane when Venable
Lane is improved and the barriers to the two approaches are removed. This traffic
will not be diverted until the road is improved by this development; therefore will
only affect total traffic conditions.
■ The three access points on Venable Lane will operate at acceptable levels of service
under total traffic conditions.
■ Venable Lane will operate at better than level of service D under total traffic
conditions, which is acceptable for a collector road.
■ The site will impact Ridgebury Avenue and Indian Rocks Street, local roads. Under
total traffic conditions, the total volume on these roads is anticipated to be less than
1,000 vehicles per day.
■ All internal roads will carry less than 1,000 vehicles per day under total traffic
conditions.
S:• projectsl18-08 Summertown Wocs &mmertown TIS. docx Page 19
Thompson Engineers
f is and Civic
Traffic Inc.
Traffic Impact Study
Summertown Subdivision, Meridian, Idaho
APPENDIX
Scope of work
Traffic Counts
Off Site Traffic
AM HCS Calculations
PM HCS Calculations
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