A-4 Update on Lake Drive and Dakota Avenue Traffic StudyCITY OF
CHANNASSEN
7700 Market Boulevard
PC Box 147
Chanhassen, MN 55317
Administration
Phone: 952.227.1100
Fax: 952.227.1110
Building Inspections
Phone: 952.227.1180
Fax: 952.227.1190
Engineering
Phone: 952.227.1160
Fax: 952.227.1170
Finance
Phone: 952.2271140
Fax: 952.227.1110
Park & Recreation
Phone: 952.227.1120
Fax: 952.227.1110
Recreation Center
2310 Coulter Boulevard
Phone: 952.227.1400
Fax: 952.227.1404
Planning &
Natural Resources
Phone: 952.227.1130
Fax: 952.227.1110
Public Works
7901 Park Place
Phone: 952.227.1300
Fax: 952.227.1310
Senior Center
Phone: 952.227.1125
Fax: 952.2271110
Web Site
www.ci.chanhassen.mn.us
14-4
lac• IM N Dili u•J
TO: Todd Gerhardt, City Manager
U
FROM: Paul Oehme, Director of Public Works /City Engineer
DATE: June 23, 2014 G
SUBJ: Traffic Study at Dakota Avenue and Lake Drive
BACKGROUND
City staff has completed a traffic study at the intersection of Dakota Avenue and
Lake Drive East.
The Sinclair gas station site was approved by the City Council for redevelopment
into a strip mall at this intersection. When the nearby residents were notified of
the redevelopment, the City received comments concerning the operations and
safety concerns at the intersection of Dakota Avenue and Lake Drive East.
Engineering staff investigated the intersection for safety and operation to see if
modifications to the intersection are warranted.
Staff will give a brief overview of the study and discuss with Council if any future
action is warranted.
Attachment: Traffic Study Analysis
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Chanhassen is a Community for Life - Providing for Today and Planning for Tomorrow
CITY OF
BACKGROUND
Fax: 952.227.1190
MEMORANDUM
The property at 7910 Dakota Avenue, formerly a Sinclair gas station, was approved
CHONSEN
by City Council to be redeveloped into a strip mall earlier this June. When the nearby
Phone: 952.227.1160
residents were notified of the development, the City received comments concerning
TO:
Paul Oehme, Director Public Works /City Engineer
7700 Market Boulevard
investigated the intersection for safety and operation to see if modification of the
Finance
PO Box 147
FROM:
Stephanie Bartels, Project Engineer V�*V
Chanhassen, MN 55317
CRASH HISTORY
DATE:
June 6, 2014
Administration
Staff obtained crash history at this intersection from the Minnesota Department of
Fax: 952.227.1110
Phone: 952.227.1100
SUBJ:
Traffic Analysis of Intersection at Dakota Avenue and Lake Drive East
Fax: 952.227.1110
possible injury accidents reported.
Phone: 952.227.1400
Building Inspections
Phone: 952.227.1180
BACKGROUND
Fax: 952.227.1190
The property at 7910 Dakota Avenue, formerly a Sinclair gas station, was approved
Engineering
by City Council to be redeveloped into a strip mall earlier this June. When the nearby
Phone: 952.227.1160
residents were notified of the development, the City received comments concerning
Fax: 952.227.1170
the intersection at Dakota Ave and Lake Drive East. The engineering staff
investigated the intersection for safety and operation to see if modification of the
Finance
Phone: 952.227.1140
intersection is warranted.
Fax: 952.227.1110
CRASH HISTORY
Park & Recreation
Phone: 952.227.1120
Staff obtained crash history at this intersection from the Minnesota Department of
Fax: 952.227.1110
Transportation (MnDOT), which keeps records of collision data throughout the state.
Recreation Center
In the past five years, there have been one property damage accident and three
2310 Coulter Boulevard
possible injury accidents reported.
Phone: 952.227.1400
Fax: 952.227.1404
Upon further investigation of the four crashes, two were caused by a driver reportedly
chemically impaired. The remaining two were caused by distracted driving and
Planning &
Natural Resources
involved drivers under the age of 18 years old.
Phone: 952.227.1130
Fax: 952.227.1110
The crash data reported at this intersection does not indicate a safety problem.
Public Works TRAFFIC DATA COLLECTION
7901 Park Place
Phone: 952.227.1300
Fax: 952.227.1310 Staff set out speed counters on Dakota Avenue north of the intersection with Lake
Drive East from May 13th through 16tH
Senior Center
Phone: 952.227.1125 The drivers coming south off of State Highway 5, had a mean 85th percentile speed of
Fax: 952.227.1110 23.8 miles per hour. The 85h percentile speed is the speed the 85% of the traffic
Web site observed was traveling under. This speed is well below the posted 30 mph speed
www.ci.chanhassen.mn.us limit and doesn't warrant any changes.
The drivers going northbound to enter onto State Highway 5 had a mean 85th
percentile speed was 26.5 miles per hour. However there were some outliers in this
g:\eng \traffic counts\2014 \dakota n of lake dr \140606_traffic analysis dakota ave & lake drive.doc
Chanhassen is a Community for Life - Providing for Todayand Planning for Tomorrow
data. 0.1 % of drivers were observed going 40 miles per hour or faster. Consistent high speeds were
not observed on Dakota Avenue during our data collection. Police enforcement may be an effective
tool for dealing with the few speeders.
One May 140' and 150', 2014, staff collected traffic data at the Dakota Avenue and Lake Drive East
intersection. See the table below for the mean number of vehicles observed during the peak hour.
The major traffic movements are westbound Lake Drive E to northbound Dakota Avenue with a
peak flow rate of 168 vehicles per hour and southbound Dakota Avenue to eastbound Lake Drive E
with a peak flow rate of 120 vehicles per hour. See figure below:
The traffic coming from Dakota Avenue south of the intersection is very low in comparison. This
intersection functions at acceptable levels because of this. The small amount of traffic Dakota
Avenue, allows nearly free right turns from westbound Lake Drive East.
Truck count data was collected on May 150i during the PM rush hour. This data shows that truck
traffic accounts for approximately 1.5% of the traffic at this intersection.
The future traffic at this intersection could be impacted by a nearby warehouse facility at 19011 Lake
Drive East. The approximately 157,000 square -foot building, which used to house SUPERVALU
distribution, is currently vacant. If the site is leased again for a warehouse use, the percentage of
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Northbound
Dakota Avenue
Southbound
Dakota Avenue
Eastbound Lake
Drive East
Westbound Lake
Drive East
AM PEAK
59
232
122
152
PM PEAK
41
192
119
205
The major traffic movements are westbound Lake Drive E to northbound Dakota Avenue with a
peak flow rate of 168 vehicles per hour and southbound Dakota Avenue to eastbound Lake Drive E
with a peak flow rate of 120 vehicles per hour. See figure below:
The traffic coming from Dakota Avenue south of the intersection is very low in comparison. This
intersection functions at acceptable levels because of this. The small amount of traffic Dakota
Avenue, allows nearly free right turns from westbound Lake Drive East.
Truck count data was collected on May 150i during the PM rush hour. This data shows that truck
traffic accounts for approximately 1.5% of the traffic at this intersection.
The future traffic at this intersection could be impacted by a nearby warehouse facility at 19011 Lake
Drive East. The approximately 157,000 square -foot building, which used to house SUPERVALU
distribution, is currently vacant. If the site is leased again for a warehouse use, the percentage of
gAeng\traffic coants\2014 \dakota n of lake dr \I40606_traffic analysis dakota ave & lake drive.doe
traffic through this intersection would increase an estimated 10% during PM Peak Time, per the ITE
Trip Generation, 6t' Ed. The percentage of truck traffic would increase as well. This increase in
traffic would not likely warrant a stop sign or signal light at this intersection, nonetheless, any traffic
impacts will be dependent on what type of future use or development occurs at this location.
SIGNAL & 4 -WAY STOP ANALYSIS
A multi -way stop sign warrant analysis was completed for the Dakota Avenue /Lake Drive
intersection per the Minnesota Manual on Uniform Traffic Control Devices
The results of the analyses are:
• Criteria A — Interim measure until traffic signal is installed: The forecast traffic volumes will
not meet the criteria for installing a traffic signal, therefore this criteria is not met.
• Criteria B — Five or more reported crashes in a 12 month period that could be corrected by all
way stop sign installation: From 2007 through 2012 there have been four total crashes
therefore this criteria is not met. It should be noted, per MnDOT's Traffic Safety
Fundamentals Handbook, that intersections controlled have all way stop sign control or side
street stop sign control have crash rates twice as high as intersections controlled with side
street stop sign control.
• Criteria C — 300 vehicles per hour on the major street approaches and 200 vehicles per hour
on the minor street approaches for each of at least eight hours per day plus minor street delay
of at least 30 seconds per vehicle in the peak hour: Based on the data collected the volume
criteria is not met plus the minor street peak hour delay is forecast to be 22 seconds per
vehicle. This forecast was built in Vissim Traffic modeling software which was completed by
a consultant.
• Criteria D —80% of Criteria B and C are met: This criteria is not met due to the low number
of crashes.
Since a 4 -way stop sign warrant is not meet a signal warrant would also not be met. A 4 -way stop
would also need to be approved by MnDOT. The Dakota Avenue & Lake Drive East intersection is
approximately 290 feet from Dakota Avenue's intersection with State Highway 5. A 4 -way stop
could cause traffic to back up to the Highway 5 intersection at peak hours of operation and interfere
with intersection operations. It is unlikely MnDOT would approve a 4 -way stop installation at this
intersection.
Staff does not recommend a 4 -way stop at this intersection.
3 -WAY STOP ANALYSIS
An additional stop sign installed on the southern approach of Dakota Avenue was also examined. It
would be unlikely to improve traffic or safety at this intersection due to the relatively small amount
of traffic that enters the intersection from this approach. During Peak Hour, less than 10% of
vehicles entering the intersection come from the south approach. Adding a stop condition to the
northbound approach also is not a recognized intersection configuration by the State of Minnesota.
Staff does not recommend a 3 -way stop at this intersection.
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Alternative to stop signs or signals, the engineering department has sketched some designs for the
intersection that may improve operations and pedestrian movements. Staff examined the geometry
of extending the median to provide greater pedestrian comfort and safety, installing a full -size or
mini roundabout. Roundabouts have been used successfully to improve traffic flow, intersection
operation and pedestrian movements. However roundabouts, like signals and stop signs, need to
meet certain traffic warrant to be installed. Also impacts to the area need to be reviewed to
determine the benefit of the improvement.
Concept 1: Full -Sized Roundabout
A full sized roundabout allows truck traffic
to easily navigate the curves, while calming
traffic as it goes through the intersection.
Roundabout design is beneficial where
there are a high number of left turns as is
the case at this intersection.
This concept is not recommended because
of the amount of right -of -way acquisition
that would be required. It would also limit
or remove access for several properties
near the intersection.
Concept 2: Mini - Roundabout
Mini - roundabout design has many of the
benefits of the full- roundabout design. It
provides traffic calming to vehicles
entering the intersection. It can be
beneficial where you have a lot of left -
turns. The smaller radius (45 feet) would
also reduce the amount of right -of -way
needed to construct. McDonald's would
likely be limited to one access and the
driveway of the property on the southeast
corner may have to be adjusted.
The small roundabout radius makes the turning move more of a challenge for trucks and large
vehicles. The center island is designed to be surmountable, so that trucks can drive over it for left
turns. Truck may also make a full circle around in order to turn right at tight corners, like the
southbound Dakota Avenue to westbound Lake Drive E. The location in the City's street network
would also allow truck drivers to bypass this intersection if necessary.
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Concept 3: Extended Median
The extended median design keeps the
traffic functions similar to the existing
condition. However, in response to
resident concerns about pedestrian
safety, the extended median would
provide a pedestrian refuge.
The pedestrian refuge will permit
pedestrians to cross one direction of
traffic at a time, allowing them to focus
on one or two lanes rather than having
to anticipate traffic for the entire width
of the road. If this improvement is
constructed, a pedestrian will have to
cross no more than two lanes of traffic
(24 feet) of pavement at a time.
This improvement is predicated on the Sinclair Station redeveloping since left turns on Dakota
Avenue would be eliminated from the gas station if the median is extended.
Adding painted crosswalks to the east or west approaches of the intersection is not recommended at
this time because there is no sidewalk or trail south of the intersection to carry pedestrians. For a
painted crosswalk to be considered, a sidewalk or trail would need to be installed on the south side of
Dakota Avenue or Lake Drive East.
Conclusions
The speed and crash data show that the intersection does not meet stop sign or signal warrants.
Therefore, a major reconstruction of how traffic operates at this intersection functions is not
warranted at this time.
The residents have expressed concern about pedestrian safety at the intersection. To improve
pedestrian mobility, engineering staff recommends extending the existing median on Dakota Avenue
down to the intersection with Lake Drive East as shown in Concept 3. The median would include a
pedestrian refuge for pedestrians traveling through this intersection. This improvement is predicated
on the Sinclair Station redeveloping. Adding painted crosswalks to the east or west approaches of
the intersection would require sidewalk or a trail to be constructed.
City staff will be discussion the traffic study with the City Council and see if they think
improvements are necessary. Staff plans to meet with the Dakota Avenue neighborhood on the
traffic finds soon.
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