ST9302-AG001024 MEMORANDUM
FROM THE
DEPARTMENT OF ENGINEERING
To:
From:
Date:
RE:
Mayor and City Council
Kenneth M. Griff'm, P.E., Dir. of Engineering/Public Works ~--/
October 24, 2000
Work Session: Discussion regarding restricting access at the intersection of
Mockingbird and Sandy Lake Road.
Because of the sequencing of construction necessary to complete Sandy Lake Road between
Samuel and MacArthur, a visibility problem has been created at the intersection of
Mockingbird with Sandy Lake Road. More specifically, it is very difficult to determine if
there is on-coming traffic and the speed of on-coming traffic as you attempt to exit
Mockingbird at Sandy Lake Road.
Initially, the north side of Sandy Lake Road was constructed to allow for westbound traffic.
The eastbound traffic remained on the old existing section of Sandy Lake Road. The
elevation of Sandy Lake in the vicinity of Samuel and Mockingbird is being cut
approximately 4 to 5 feet. Therefore, you currently have a section of roadway where the new
westbound section is approximately 4 to 5 feet lower than the old existing eastbound section,
which is about 4 to 5 feet higher than the intersection of Mockingbird (see Exhibit B).
Because of the drop-off, barriers needed to be placed along the edge of the old existing section
of Sandy Lake Road. These barriers, while providing safety to the traveling cars on Sandy
Lake Road, are creating a visibility problem for vehicles trying to exit Mockingbird to either
cross or enter Sandy Lake Road. This situation will exist for approximately three months.
The old existing section of Sandy Lake Road, where the eastbound traffic is, cannot be
lowered at this time because directly beneath that section is the City of Dallas' water line that
supplies water to the Town of Flower Mound. That water line will be lowered as part of this
project; however, it cannot be taken out of service until a new City of Dallas water line is
installed parallel to the existing line. Once the new line is installed, the old water line will be
taken out of service, connected to the new water line at both ends and then the old existing
section of Sandy Lake Road can be removed.
Because of the safety and visibility issues, several alternatives have been explored:
1. Remove the barricades on the south side of old Sandy Lake Road; this creates a safety
hazard for vehicles traveling on old Sandy Lake Road.
2. Close off Mockingbird in its entirety at Sandy Lake Road; this will restrict vehicles
leaving Mockingbird to enter Sandy Lake Road and vehicles on Sandy Lake trying to
enter Mockingbird. Because of the middle school on Mockingbird and because
Mockingbird is a collector street which carries southbound traffic, restricting access from
"CITY OF COPPELL ENGINEERING - EXCELLENCE BY DESIGN"
~andy Lake to Mockingbird could worsen morning traffic patterns in and around the
area.
3. Restrict northbound traffic on Mockingbird from entering Sandy Lake Road; this option
still allows vehicles on Sandy Lake to turn onto Mockingbird to access the middle school
or to utilize Mockingbird to get to Belt Line Road for traffic movement in the mornings.
However, it eliminates vehicles trying to exit Mockingbird to enter Sandy Lake. That is
the traffic maneuver which has the limited visibility and the safety concerns. If you
restrict vehicles from leaving Mockingbird to enter Sandy Lake Road, those vehicles still
have several other options available to them: 1) to utilize Eagle to Raven to Sandy Lake
Road; 2) to utilize Swallow or Sparrow to Quaff to Moore to Sandy Lake. Vehicles
further south on Mockingbird could use any of those options in addition to Oriole to
Shadowcrest to Moore to Sandy Lake or Cherrybark to Sugarberry to Mapleleaf to
Sandy Lake Road (see Exhibit A).
Each of the above options route northbound traffic on Mockingbird onto residential side
streets to access other streets that intersect Sandy Lake Road. This would be an
inconvenience for the period of time that Mockingbird is closed off from accessing Sandy
Lake Road; however the safety issues should outweigh the inconvenience. We are aware that
there is also a percentage of the vehicles utilizing Mockingbird to directly access the shopping
center on the north side of the intersection. Routing those vehicles to Moore, Raven or
Sugarberry takes them out of the way; but again, it provides them a safer maneuver as
opposed to trying to cross Sandy Lake Road at Mockingbird.
Staff supports Option #3 that restricts access from Mockingbird to Sandy Lake Road. If
Council approves this item, then notices will be sent to the residents along Mockingbird,
Eagle, Swallow, Sparrow, Quaff, and Raven to alert them that for a period of time vehicles
could be utilizing those residential side streets because of the closure of Mockingbird at
Sandy Lake Road.
Staff will be available at the Council meeting to answer any questions.
"CITY OF COPPELL ENGINEERING - EXCELLENCE BY DESIGN"