Vlg at CC S2/PP-CS 920501MAY 1 , 1992
TO:
MAYOR AND CITY COUNCIL MEMBERS,
CITY OF COPPELL
SUBJECT:
REVISED PLATT ()? VII,LAGE ^T COTT~qNWOOD CREEK II
FROM:
THE APPOINTED TRAfFiC i.;OMM['I'TEE, VI!~!.,AGE AT COTTONWC)OD
OMEO~NERS
CREEK H ; ' ~' ,~SStC'.A'['ION
Honorable Mayor and members of the council: We, the Traffic
Committee of V.A.(].C., respectful l_y request your consideration
and support of the revised portion of the subject platt shown
as attachment i. After careful consideration of the previously
proposed platt, we are recommending minor changes that are in
the best interest of the V.A.C.C. neighborhood. And which
effectively resolve traffJc safety issues previously identified
and discussed during the revic, w and pr(',~::entation of the orJ. ginal
platt.
If not previously contacted, we would request an audience with
each of you Jn the very near future (prior to the May 12 council
meeting) to fully communic, at:(~ t,~ ~se rec~mmendat~ons.
Respectfully 5'ours,
¥.A.C.C. Traffic Committee
Ann Hinson
Donna Benham
David Smith
393-1433
393-1120
462-7244
MEMO
TO:
FROM:
SUBJECT:
DATE:
Alan D. Ratliff, City Manager
Kenneth M. Griffin, P.E., City Engineer
Traffic Issues Associated with the Replat
of Villages of Cottonwood Creek Phase II
April 24, 1992
Based on our meeting of April 23, 1992, it's my understanding that in
conjunction with the replat of the Villages of Cottonwood Creek Phase II,
the engineering department should be investigating the following items:
1)
The installation of a no-left turn si~n at the intersection of
Gibson with Misty Haven.
2)
The installation of a multi-way stop sign at the intersection
of Burning Tree with Winding Hollow.
3) The design capacity of Winding Hollow.
4) The installation of speed bumps on Winding Hollow.
The following represents a brief discussion of each of these items and a
projected time when they can be completed for implementation:
1) No-left turn - Gibson with Misty Haven.
The Texas Manual on Uniform Traffic Control Devices does not address
any specific warrants for the installation of a no-left turn sign.
It is my understanding that the request is to have left turns
restricted to coincide with the start and end of the school day, i.e.
no-left turns from 7:00 a.m. to 8:30 a.m. and no-left turns from 3:00
p.m. to 4:30 p.m.
2)
The installation of a multi-way stop sign - Burning Tree with Winding!
Hollow.
The Texas Manual Uniform Traffic Control Devices provides basic
warrants and an alternate set of warrants for the installation of
multi-way stop signs. The engineering department will perform an
analysis of this intersection to determine if it meets the warrants
as determined by the Texas Manual Uniform Traffic Control Devices.
Memo to Alan D. Ratliff, City Manager
April 24, 1992
Page 2
3)
4)
The engineering department took traffic counts on March 12, 1992
along Winding Hollow. Those counts are provided with this memo.
They indicate a 24-hour traffic volume of 225 vehicles north of
Burning Tree and 965 vehicles south of Burning Tree. Because of
these low traffic volumes, it is doubtful that this intersection will
meet the warrants for a multi-way stop sign. If the intersection
fails to meet the warrants, the engineering department could perform
a follow-up warrant study, once the subdivision to the north is built
out.
Based on generally accepted transportation designs, a single family
residence typically has 10 vehicle trips per residence per day. If
the entire east part of the subdivision to the north were to exit
Gibson and drive down Winding Hollow, the traffic on Winding Hollow
could theoretically double, i.e. go from approximately 1,000 to
approximately 2,000.
Capacity of Winding Hollow.
Based on our roadway functional classifications and design standards
prepared by Barton-Aschman Associates in 1990, the capacity of a
residential street is 5,000 vehicles per day. This is a substantial
amount of traffic. However, as indicated above, the current volume
is approximately 1,000 vehicles a day and the anticipated worst case
scenario for the future is approximately 2,000 vehicles a day.
Therefore, Winding Hollow should have sufficient capacity to convey
the traffic.
Installation of speed bumps.
It is my opinion that the typical parking lot speed bump should not
be utilized on a public street. This opinion is shared by most
transportation professionals. A speed bump on a typical residential
street provides significant driver discomfort and generally results
in vehicles slowing to almost a complete stop to cross the bump. As
an alternative to the speed bumps, at the May 12, 1992 City Council
meeting, I will make a presentation on the use of road hump~.
In July 1988, the Institute of Transportation Engineers commissioned
a special task force to review alternative ways to control traffic in
residential areas. Coming out of that task force was the concept
behind the utilization of speed humps in residential areas to deter
and slow down traffic. The basic difference between a speed bump and
a road hump is that the speed bump is typically about 1 foot long and
rises about 4 to 6 inches, whereas, the road hump is 12 foot long and
rises 3 to 4 inches. As you can see, the speed bump gives a sudden
jar, whereas the road hump gives a general rise in the surface.
Memo to Alan D. Ratliff, City Manager
April 24, 1992
Page 3
The concept behind road humps was originally developed in the early
1970's by the Transport and Road Research Laboratory in Great
Britain. They have been tested and utilized in areas should as
Europe, Australia, New Zealand, and have also been tested by the U.S.
Federal Highway Administration. Locally, the City of Dallas has a
road hump policy. They have used the road humps for approximately 2
1/2 years on McCommas. It also has been utilized on several other
streets in Dallas.
Again, a presentation will be made at the May 12, 1992 City Council
meeting concerning the usage of road humps.
The study on the multi-way stop signs at Burning Tree and Winding Hollow
and a recommendation for the "no left turn" sign at Gibson and Misty Haven
should be completed by the end of May.
If you should have any questions or need any additional information,
please feel free to contact me at your convenience.
Sincerely,
Kenneth M. Griffin, P.E.
City Engineer
KMG/bd
cc: Gary L. Sieb, Director of Planning and Community Services
COTTON