Traffic Impact Study 01-08-2015
Traffic Impact Study for
Children’s Learning Adventure Childcare Center
in Chanhassen, MN
Prepared for:
Children’s Learning Adventure Childcare Centers
Prepared by:
WENCK ASSOCIATES, INC.
1800 Pioneer Creek Center
P.O. Box 249
Maple Plain, Minnesota 55359-0249
(763) 479-4200
Wenck File #5262-01
January 8, 2015
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January 2015
Table of Contents
1.0 EXECUTIVE SUMMARY .............................................................................................. 1-1
2.0 PURPOSE AND BACKGROUND ................................................................................... 2-1
3.0 EXISTING CONDITIONS .............................................................................................. 3-1
4.0 TRAFFIC FORECASTS.................................................................................................. 4-1
5.0 TRAFFIC ANALYSIS .................................................................................................... 5-1
6.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................. 6-1
7.0 APPENDIX ................................................................................................................. 7-1
FIGURES
FIGURE 1 PROJECT LOCATION ............................................................................................ 2-2
FIGURE 2 SITE PLAN ............................................................................................................ 2-3
FIGURE 3 EXISTING CONDITIONS ........................................................................................ 3-2
FIGURE 4 WEEKDAY AM AND PM PEAK HOUR TURN MOVEMENT VOLUMES .................. 4-3
FIGURE 5 WEEKDAY AM AND PM PEAK HOUR LEVEL OF SERVICE RESULTS ...................... 5-4
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1.0 Executive Summary
The purpose of this Traffic Impact Study is to evaluate the traffic impacts of the proposed Children’s
Learning Adventure Childcare Center in Chanhassen, MN. The project site is located in the northwest
corner of the TH 5/Galpin Boulevard intersection. The proposed project location is currently vacant.
Based on discussions with City staff, this study examined weekday a.m. and p.m. peak hour traffic
impacts of the proposed redevelopment at the following intersections:
Galpin Boulevard/W. 78th Street
Galpin Boulevard/proposed access
W. 78th Street/proposed access
Proposed Development Characteristics
The proposed project will involve construction of a 33,000 square foot building that will house the
proposed child care center. The expected enrollment for the center is 375 students. The project
includes 142 on-site parking spaces.
As shown in the site plan, the project includes access on both W. 78th Street and Galpin Boulevard. The
access on Galpin Boulevard is restricted to right turns only by the existing raised median. The access on
W. 78th Street is a full access intersection.
The proposed project is expected to be completed by the end of 2016.
The northern portion of the site could potentially be developed in the future. This study does not
account for any development other than the proposed child care center. If additional development is
proposed in the future, the traffic analysis should be updated accordingly.
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The conclusions drawn from the information and analyses presented in this report are as follows:
The proposed development is expected to generate a net total of 220 trips during the a.m. peak
hour and 200 trips during the p.m. peak hour.
Traffic generated by the proposed project does not change the level of service of any movement
to an unacceptable level during either peak hour. No improvements are needed at the
intersections analyzed to accommodate the proposed project.
Observations showed that the northbound u-turn movement at Galpin Boulevard/W. 78th Street
operated with minimal conflicts to other traffic accessing the intersection. Adequate space is
provided on Galpin Boulevard to allow vehicles to complete the u-turn in one movement with
minimal delay. In addition, adequate sight distance is provided to the north, allowing turning
vehicles enough time to complete the movement efficiently.
The proposed right turn access on Galpin Boulevard will result in increases to the northbound u-
turn volume at Galpin Boulevard/W. 78th Street. As shown in the level of service analysis, the
increase in u-turns does not impact the left turn level of service. The increase in u-turns does
not significantly impact the intersection operations.
Traffic observations during the a.m. and p.m. peak hours indicate that adequate space is
available between T.H. 5 and the proposed right turn access. We do not anticipate vehicle
queuing impacts at this location.
The project trips have minimal impact on the overall traffic operations. No improvements are
needed to the surrounding street system to accommodate the proposed project. The proposed
right turn access on Galpin Boulevard provides a secondary access for the site, resulting in
greater dispersion of traffic onto the surrounding roadway system.
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2.0 Purpose and Background
The purpose of this Traffic Impact Study is to evaluate the traffic impacts of the proposed Children’s
Learning Adventure Childcare Center in Chanhassen, MN. The project site is located in the northwest
corner of the TH 5/Galpin Boulevard intersection. The proposed project location is currently vacant.
The project location is shown in Figure 1.
Based on discussions with City staff, this study examined weekday a.m. and p.m. peak hour traffic
impacts of the proposed redevelopment at the following intersections:
Galpin Boulevard/W. 78th Street
Galpin Boulevard/proposed access
W. 78th Street/proposed access
Proposed Development Characteristics
The proposed project will involve construction of a 33,000 square foot building that will house the
proposed child care center. The expected enrollment for the center is 375 students. The project
includes 142 on-site parking spaces. The current site plan is shown in Figure 2.
As shown in the site plan, the project includes access on both W. 78th Street and Galpin Boulevard. The
access on Galpin Boulevard is restricted to right turns only by the existing raised median. The access on
W. 78th Street is a full access intersection.
The proposed project is expected to be completed by the end of 2016.
The northern portion of the site could potentially be developed in the future. This study does not
account for any development other than the proposed child care center. If additional development is
proposed in the future, the traffic analysis should be updated accordingly.
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FIGURE 1 PROJECT LOCATION
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FIGURE 2 CURRENT SITE PLAN
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3.0 Existing Conditions
The proposed site is currently vacant. The site is bounded by Galpin Boulevard on the east, W. 78th
Street on the north and west, and T.H. 5 on the south.
Near the site location, Galpin Boulevard is a four lane divided roadway with turn lanes at major
intersections. W. 78th Street is a two lane roadway that serves as a frontage road for T.H. 5. Existing
conditions at intersections near the proposed project location are shown in Figure 3 and described
below.
Galpin Boulevard/W. 78th Street
This intersection has four approaches and is controlled with stops signs on the eastbound and
westbound W. 78th Street approaches. The eastbound and westbound approaches provide one left turn
lane and one through/right turn lane. The northbound and southbound approaches provide one left
turn lane, one through lane, and one through/right turn lane.
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4.0 Traffic Forecasts
Traffic Forecast Scenarios
To adequately address the impacts of the proposed project, forecasts and analyses were completed for
the year 2017. Specifically, weekday a.m. and p.m. peak hour traffic forecasts were completed for the
following scenarios:
2014 Existing. Turn movement volumes collected in December 2014 were used for existing
conditions. The existing volume information includes trips generated by uses near the project
site.
2017 No-Build. Existing volumes at the subject intersections were increased by 1.0 percent per
year to determine 2017 No-Build volumes. The 1.0 percent per year growth rate was based on
both recent growth experienced near the site and expected future growth.
2017 Build. Trips generated by the proposed uses were added to the 2017 No-Build volumes to
determine 2017 Build volumes.
Trip Generation
The expected development trips were calculated based on detailed enrollment and employee
information obtained from the project owner. The following assumptions were used in development of
the trip generation estimates:
375 student enrollment broken down as follows:
o 225 pre-school students.
o 150 school age students, with 75 dropped off at the center in the morning and bussed to
school, and 75 brought to school in the morning and bussed to the center in the afternoon.
40 staff.
Vehicle occupancy rate of 1.2 students per car.
All pre-school students are dropped off at the center in the morning and picked up at the center
in the afternoon.
75 school age students are dropped off at the center in the morning, bussed to school in the
morning, bussed back to the center in the afternoon, and picked up at the center in the
afternoon.
75 school age students are dropped off at school in the morning, bussed back to the center in
afternoon, and picked up at the center in the afternoon.
All busing activities occur on-site. Students are not dropped off or picked up on the streets
adjacent to the site.
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Using hourly percentages presented in Trip Generation, Ninth Edition, published by the Institute of
Transportation Engineers (ITE), a.m. and p.m. peak hour trips calculated and shown below.
Table 4-1: Weekday Trip Generation for Proposed Land Use
Land Use
Weekday AM Peak Hour
Weekday PM Peak Hour
Weekday
Daily
In Out Total In Out Total Total
Proposed Use
Day Care – 375 students 121 99 220 94 106 200 1248
SF=square feet, DU=dwelling units
The trips can be categorized into the following three trip types:
New Trips - Trips solely to and from the proposed development.
Pass-By Trips - Trips that are attracted from the existing traffic volume on roadways immediately
adjacent to the site.
Diverted Trips - Trips that are attracted from the existing traffic volume on roadways nearby but
not immediately adjacent to the site.
Trip Distribution Percentages
Trip distribution percentages for the subject development trips were established based on the nearby
roadway network, existing and expected future traffic patterns, and location of the subject development
in relation to major attractions and population concentrations. The distribution percentages for trips
generated by the proposed development are as follows:
New Trips:
25 percent to/from the north on Galpin Boulevard
45 percent to/from the south on Galpin Boulevard
15 percent to/from the east on W. 78th Street
15 percent to/from the east on W. 78th Street
Pass-by Trips:
A.M. Peak Hour – 75% from the north, 25% from the south
P.M. Peak Hour – 50% from the north, 50% from the south
Diverted Trips:
A.M. Peak Hour – 70% from the west, 30% from the east
P.M. Peak Hour – 35% from the west, 65% from the east
Traffic Volumes
Development trips were assigned to the surrounding roadway network using the preceding trip
distribution percentages. Traffic volumes were established for all the forecasting scenarios described
earlier during the weekday a.m. and p.m. peak hours. The resultant traffic volumes are presented in
Figure 4.
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FIGURE 4 WEEKDAY PM PEAK HOUR TRAFFIC VOLUMES
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5.0 Traffic Analysis
Intersection Level of Service Analysis
Traffic analyses were completed for the subject intersections for all scenarios described earlier during
the weekday a.m. and p.m. peak hours using Synchro software. Initial analysis was completed using
existing geometrics and intersection control.
Capacity analysis results are presented in terms of level of service (LOS), which is defined in terms of
traffic delay at the intersection. LOS ranges from A to F. LOS A represents the best intersection
operation, with little delay for each vehicle using the intersection. LOS F represents the worst
intersection operation with excessive delay. The following is a detailed description of the conditions
described by each LOS designation:
Level of service A corresponds to a free flow condition with motorists virtually unaffected by the
intersection control mechanism. For a signalized or an unsignalized intersection, the average
delay per vehicle would be approximately 10 seconds or less.
Level of service B represents stable flow with a high degree of freedom, but with some influence
from the intersection control device and the traffic volumes. For a signalized intersection, the
average delay ranges from 10 to 20 seconds. An unsignalized intersection would have delays
ranging from 10 to 15 seconds for this level.
Level of service C depicts a restricted flow which remains stable, but with significant influence
from the intersection control device and the traffic volumes. The general level of comfort and
convenience changes noticeably at this level. The delay ranges from 20 to 35 seconds for a
signalized intersection and from 15 to 25 seconds for an unsignalized intersection at this level.
Level of service D corresponds to high-density flow in which speed and freedom are significantly
restricted. Though traffic flow remains stable, reductions in comfort and convenience are
experienced. The control delay for this level is 35 to 55 seconds for a signalized intersection and
25 to 35 seconds for an unsignalized intersection.
Level of service E represents unstable flow of traffic at or near the capacity of the intersection
with poor levels of comfort and convenience. The delay ranges from 55 to 80 seconds for a
signalized intersection and from 35 to 50 seconds for an unsignalized intersection at this level.
Level of service F represents forced flow in which the volume of traffic approaching the
intersection exceeds the volume that can be served. Characteristics often experienced include
long queues, stop-and-go waves, poor travel times, low comfort and convenience, and increased
accident exposure. Delays over 80 seconds for a signalized intersection and over 50 seconds for
an unsignalized intersection correspond to this level of service.
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The LOS results for the study intersections are described below and shown in Figure 5. All LOS
worksheets are included in the Appendix for further detail.
Galpin Boulevard/W. 78th Street (minor street stop sign control)
During the a.m. peak hour under all scenarios, all movements operate at LOS C or better. The overall
intersection operates at LOS A.
During the p.m. peak hour under all scenarios, all movements operate at LOS C or better. The overall
intersection operates at LOS A.
Traffic generated by the proposed project does not change the level of service of any movement to an
unacceptable level during either peak hour. No improvements are needed at this intersection to
accommodate the proposed project.
Galpin Boulevard/Site Access (minor street stop sign control)
During the a.m. peak hour under all scenarios, all movements operate at LOS A. The overall intersection
operates at LOS A.
During the p.m. peak hour under all scenarios, all movements operate at LOS A. The overall intersection
operates at LOS A.
No improvements are needed at this intersection to accommodate the proposed project.
W. 78th Street/Site Access (minor street stop sign control)
During the a.m. peak hour under all scenarios, all movements operate at LOS B or better. The overall
intersection operates at LOS A.
During the p.m. peak hour under all scenarios, all movements operate at LOS B or better. The overall
intersection operates at LOS A.
No improvements are needed at this intersection to accommodate the proposed project.
U-Turns at Galpin Boulevard/W. 78th Street
City staff have received complaints about u-turns at this location. Therefore, additional detailed analysis
was completed for the u-turn movement. Under existing conditions, u-turns occur in the northbound
left turn lane on Galpin Boulevard at W. 78th Street. Customers exiting from the businesses on the east
side of Galpin Boulevard are forced to travel north by the existing raised median. Those wishing to
travel south on Galpin Boulevard to T.H. 5 make a u-turn at W. 78th Street. The u-turn movement occurs
in a dedicated left turn lane and is a legal movement.
Observations at the site during both the a.m. and p.m. peak hours indicated approximately 50% of
vehicles in the left turn lane made the u-turn movement. Observations also showed that the u-turn
movement operated with minimal conflicts to other traffic accessing the intersection. Adequate space is
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provided on Galpin Boulevard to allow vehicles to complete the u-turn in one movement with minimal
delay. In addition, adequate sight distance is provided to the north, allowing turning vehicles enough
time to complete the movement efficiently.
The proposed right turn access on Galpin Boulevard will result in increases to the u-turn volume. We
estimate the u-turn volume will increase by 40 vehicles during the a.m. peak hour and 33 vehicles during
the p.m. peak hour. The level of service analyses specifically accounted for the u-turn movement by
separating the u-turns from the left turns. As shown in the level of service analysis, the increase in u-
turns does not impact the left turn level of service. Therefore, from a traffic operations perspective, the
increase in u-turns does not significantly impact the intersection operations.
Vehicle Queue Lengths on Galpin Boulevard at T.H. 5
The proposed right turn access on Galpin Boulevard will be located approximately 380 feet north of T.H.
5. The proposed location is directly across from the existing right turn access for the businesses on the
east side of the roadway. Traffic operations on Galpin Boulevard were observed during the a.m. and
p.m. peak hours to determine if southbound vehicle queues would impact operations at the proposed
right turn access location. The existing southbound left turn lane onto T.H. 5 is approximately 255 feet in
length.
During both the a.m. and p.m. peak hours, the vehicle queues in the southbound left turn lane did not
exceed the existing turn lane length. The longest queue observed in the a.m. peak hour was 9 vehicles,
which equates to approximately 200 feet. The majority of queues during the a.m. peak hour were 5
vehicles or less, equating to approximately 110 feet or less.
The longest queue observed in the p.m. peak hour was 5 vehicles, which equates to approximately 110
feet. The majority of queues during the p.m. peak hour were 3 vehicles or less, equating to
approximately 66 feet or less.
Based on these observations, there is adequate space available between T.H. 5 and the proposed right
turn access. We do not anticipate vehicle queuing impacts at this location.
Overall Traffic Impacts
As described above and shown in Figure 5, the project trips have minimal impact on the overall traffic
operations. No improvements are needed to the surrounding street system to accommodate the
proposed project. The proposed right turn access on Galpin Boulevard provides a secondary access for
the site, resulting in greater dispersion of traffic onto the surrounding roadway system.
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6.0 Conclusions and Recommendations
The conclusions drawn from the information and analyses presented in this report are as follows:
The proposed development is expected to generate a net total of 220 trips during the a.m. peak
hour and 200 trips during the p.m. peak hour.
Traffic generated by the proposed project does not change the level of service of any movement
to an unacceptable level during either peak hour. No improvements are needed at the
intersections analyzed to accommodate the proposed project.
Observations showed that the northbound u-turn movement at Galpin Boulevard/W. 78th Street
operated with minimal conflicts to other traffic accessing the intersection. Adequate space is
provided on Galpin Boulevard to allow vehicles to complete the u-turn in one movement with
minimal delay. In addition, adequate sight distance is provided to the north, allowing turning
vehicles enough time to complete the movement efficiently.
The proposed right turn access on Galpin Boulevard will result in increases to the northbound u-
turn volume at Galpin Boulevard/W. 78th Street. As shown in the level of service analysis, the
increase in u-turns does not impact the left turn level of service. The increase in u-turns does
not significantly impact the intersection operations.
Traffic observations during the a.m. and p.m. peak hours indicate that adequate space is
available between T.H. 5 and the proposed right turn access. We do not anticipate vehicle
queuing impacts at this location.
The project trips have minimal impact on the overall traffic operations. No improvements are
needed to the surrounding street system to accommodate the proposed project. The proposed
right turn access on Galpin Boulevard provides a secondary access for the site, resulting in
greater dispersion of traffic onto the surrounding roadway system.
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7.0 Appendix
Level of Service Worksheets