Item 8 - Magellan Traffic Control Recommendations
Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
March 30, 2021
Mark Brown, P.E.
Facility Integrity Engineering
Magellan Midstream Partners, L.P.
One Williams Center, MD: OTC-8
Tulsa, OK 74172
Subject: Mustang Business Park Traffic Impact Review
Mustang Court & Southwestern Street
Southlake, Texas
Request
NuStar Logistics, L.P. (“NuStar”) and Magellan Midstream Partners, L.P. (“Magellan”)
have requested Traffic Engineering Consultants, Inc. (TEC) to review the proposed
Mustang Business Park development and associated submittal documents located in
Southlake, Texas (“Project”). The Project site is located generally north and west of the
intersection of Mustang Court and State Highway (SH) 26 as shown on the following
page. NuStar and Magellan have requested a review of the Project’s traffic impact on
their current operations.
Scope of the Review
Kimley-Horn and Associates, Inc. submitted a traffic impact analysis (TIA) to the City of
Southlake on February 1, 2021. Lee Engineering reviewed the traffic impact analysis
(TIA) for the City of Southlake and submitted review comments on February 23, 2021.
The City of Southlake 2035 Corridor Planning Committee met and reviewed the
proposed project on January 25, 2021. Minutes from the meeting were available. TEC
has reviewed all the above documents and relied on these documents in the following
opinions.
Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
Recommendations
1) The proposed new driveway intersection should be moved north to create
additional separation between intersections. At a minimum, the south drive
should be relocated as shown in Figure 1 which will be discussed later in the
report.
2) 4-Way Stop control is recommended for the intersection of Southwestern Street
and Mustang Court.
3) A secondary public access roadway should be included for a development of this
size.
Existing Uses Adjacent to the Proposed Project
Magellan currently operates a fueling terminal at this location. NuStar also operates a
fueling terminal that uses the same access point. The access point is Mustang Court
which extends northwest from its intersection with SH-26. An average of 200 fuel trucks
per day (maximum day 300 trucks) use Mustang Court to access the two facilities.
Counting a trip in and a trip out for each truck, the average number of truck trips per
day is approximately 400 (maximum day 600 trips). These are semi-trailer fuel trucks.
Project Magnitude
The proposed development of the Mustang Business Park will also use Mustang Court as
its only point of access. The development proposes to extend Mustang Court northwest
to serve an approximate 341,000 square feet of warehouse with office. The site plan
shows approximately 95 loading docks for semi-trailer trucks with an equal amount of
additional trailer parking. The proposed land use will significantly increase the amount
of truck traffic on Mustang Court.
Single Access Point
The current site plan shows a new four-way driveway intersection approximately 110
feet northwest of the existing intersection of Southwestern Street and Mustang Court.
Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
Both Magellan and NuStar use the Southwestern Street intersection as their only point
of access.
Traffic Impact Study Inconsistent with the Site Plan as Reviewed
A site plan was submitted to the City of Southlake for review dated December 14, 2020.
The site plan was revised by the applicant and resubmitted February 1, 2021. A traffic
impact analysis (TIA) was conducted by Kimley-Horn and Associates, Inc. on February 1,
2021. The Kimley-Horn TIA used the site plan with 330,000 square feet as originally
submitted. The revised site plan increased the square footage by approximately 11,000
square feet.
At the City of Southlake 2035 Corridor Planning Committee meeting held on January 25,
2021 the applicant was asked why the number of parking spaces prop osed was greater
than the required number of spaces. The required number of spaces is 370 and the
proposed number of spaces is 446. The applicant indicated “We want to increase the
office use percentage to balance the space. Because they are spec buildings we want to
leave flexibility for whatever tenant comes in to utilize the space.” If the office space is
increased there will be additional traffic generated, especially in the peak hours.
Corridor Planning Committee Highlights
At the January 25, 2021 Southlake 2035 Corridor Planning Committee meeting the
applicant presented a proposed development for Light Industrial Warehouse. The total
proposed square footage was 330,980 square feet. The Kimley-Horn traffic impact
analysis was based on a rounded 331,000 square feet. To calculate the expected
number of new trips the Trip Generation category used was “Warehousing”.
Project Appears to be a Mixed-Use Development
There are several categories that could be used for a development of this type. Table 1
shows four possible classifications that could have been used for the traffic projections.
Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
Table 1 Trip Generation Projection Comparison
Vehicle
Trips per
Day
Vehicle Trips A.M.
Peak Hour
Vehicle Trips P.M.
Peak Hour
Warehousing 1.71 0.19 0.20
General Light Industrial 3.96 0.32 0.25
Industrial Park 5.22 0.40 0.40
General Office 10.83 1.46 1.18
The purpose of a TIA is to make traffic projections as close as possible to how the
property will be developed. The square footage of the development as currently
submitted is 290,000 square feet of warehouse and 51,000 square feet of office. Table
1 shows the number of trips projected for each 1,000 square feet of building for three
time periods: 1) total trips for a 24-hour period (Trips per Day), 2) trips during the
highest a.m. peak one hour, and 3) trips during the highest p.m. peak one hour. For the
combined 341,000 square feet projected development, the appropriate square footage
would be multiplied by each trip rate to calculate the number of projected trips. The
Warehousing category will project the lowest number of trips of the categories shown.
The Office category projects a much higher number of trips per square foot. The
Warehousing category assumes minimal office space. Table 1 is presented to show that
there is a potential for the furnished traffic projections to be significantly lower than
what may actually occur. Based upon a quick calculation warehousing alone would
create approximately 583 trips a day. As presented the 51,000 square feet of of fice
space will generate 552 trips per day and the warehousing would generate 496 trips per
day totaling 1,048 trips per day.
Mustang Court and Southwestern Street 4-Way Stop Analysis Not Provided
Lee Engineering reviewed the Kimley-Horn traffic impact analysis. The Lee review
highlighted that the TIA and the submitted site plan showed 330,980 square feet. A
revised site plan submitted February 1, 2021 shows a proposed 340,180 square feet
development. The Lee review pointed out the City requested a 4-Way Stop analysis for
Mustang Court and Southwestern Street which was not provided in the TIA. At a
minimum, the intersection needs to be a 4-Way Stop.
Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
Deficient Intersection Separation Distance
Lee Engineering correctly states in item 17, “If the new Mustang Court private street
extension is considered a part of the site and thus a driveway, there does not appear to
be enough internal storage between the Southwestern Street intersection and the first
internal circulation aisles”. The city’s subdivision regulations and the street and right of
way requirements require a minimum separation of 150 feet between these
intersections. These codes assume regular vehicular traffic. When there is a large
percentage of trucks the spacing should be even greater. The new intersection will only
have a centerline-to-centerline separation of approximately 110 feet.
Analysis of Project Truck Wheel Paths
Figure 1 on the following page is an exhibit of the tracking path of the wheels and trailer
for a 67-foot wheelbase semi-trailer truck making a northbound right turn from the
proposed driveway onto Mustang Court in the proposed development.
Alternative 1 shows a truck path where the truck does not cross the centerline of
Mustang Court. For Alternative 1 a right curb return radius would have to be
constructed that would extend beyond the existing intersection of Southwester Street
and Mustang Court. In order to accommodate the larger radius it would require a
greater separation between the two intersections.
Alternative 2 shows the wheel path If the truck is permitted to cross both the driveway
centerline and the Mustang Court centerline. This turn could be made with the existing
pavement design. However, the truck will be on the wrong side of the road at the
intersection of Southwestern Street and Mustang Road. With 4-Way Stops the truck will
be in the opposing lane. Neither alternative is recommended.
Alternative 3 is the preferred alternate and would be to relocate the northbound drive
to the west adjoining and attaching to the proposed dead-end driveway on the east side
of the building. The alternative would also eliminate a dead-end parking aisle which is
not desirable.
The turning radii were also checked for the southbound driveway. The southbound left
turn can be made as designed. It should be noted executing the northwest right turn to
this driveway would cross the centerline of the driveway.
NEW CURB
ALTERNATIVE 1,
NEW THRU ROAD
ALTERNATIVE 3,
OUTSIDE WHEEL PATH
ALTERNATIVE 2,
OUTSIDE WHEEL PATH
ALTERNATIVE 1,
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Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
Project Impacts on Existing Uses
There are several factors that should be considered that have the potential to create
operational impacts on the Magellan and NuStar operations. The existing land uses and
the proposed land uses have a high percentage of semi-trailer trucks. These vehicles
take more space to maneuver and take more time to proceed through inte rsections.
The factors of concern are:
1) The amount of increased traffic that will use the 3-lane signalized approach of
Mustang Court at SH-26 would create significant delays. It seems apparent that
very little, if any, additional green time can be assigned to Mustang Court.
2) The Magellan and NuStar operations are primarily gasoline semi-trailers. These
trucks are required to stop at the railroad track across the north leg of Mustang
Court which reduces the capacity of the traffic signal even more. All vehicles are
required to stop in advance of the railroad crossing while waiting for a green
light because of the lack of storage space between the tracks and SH-26. There
is also no right turn on red allowed for Mustang Court.
3) The fact that the proposed development is primarily a large truck warehouse
district the development will significantly increase the number of trucks using
Mustang Court somewhere between 300 and 400 trips per day. This is in
addition to an estimated 200 to 300 passenger car trips.
4) The proposed development is only showing one point of access (Mustang Court)
without the ability to mitigate traffic impacts to a second access point. Typically,
developments of this size are required to have at least two points of access for
safety reasons. An emergency access through the neighborhood to the north is
shown. However, for a development of this size, it is de sirable to have an
additional public access point to another roadway.
5) The spacing of the first driveways in the new development are too close to the
existing intersection of Mustang Court and Southwestern Street. There will not
be adequate storage and the driveways will have an adverse impact on the
existing intersection of Mustang Court and Southwestern Street.
Traffic Engineering Consultants, Inc.
6000 S. Western Avenue, Suite 300 | Oklahoma City, Oklahoma 73139 | Ph. 405-720-7721
6931 S. 66th E. Avenue, Suite. 100 | Tulsa, Oklahoma 74133 | Ph. 918-481-8484
217 E. Dickson Street, Suite 106 | Fayetteville, Arkansas 72701| Ph. 479-335-5636
Website: www.tecusa.com
6) If the project is constructed 4-way stop control should be implemented at
Mustang Court and Southwestern Street to adequately serve the traffic f rom
Magellan and NuStar operations.
7) The site plan square footages have increased since original submission. The
applicant has stated the site plan is speculative in nature and they desire to have
flexibility to increase the office use. If either the square footage increases or the
office use increases, the projected traffic in the traffic impact analysis would be
understated.
Conclusion
Based upon our review of the above documents we make three recommendations that
should be applied to the project.
• The proposed new driveway intersection should be moved north to create
additional separation between intersections. At a minimum, the south drive
should be relocated as shown in Figure 1.
• 4-Way Stop control is recommended for the intersection of Mustang Court and
Southwestern Street.
• A secondary public road access should be included for a development of this
size.
Sincerely,
Steven D. Hofener, P.E., PTOE
Principal | Traffic Engineering Consultants, Inc.
SDH/slj
TO-923