TR8901-PR 890720July 20, 1989
City of Coppell
255 Parkway Boulevard
Coppell, Texas 75019
Re: Traffic signals on Denton Tap Road at Bethel School Road and
at Parkway Boulevard.
Gentlemen:
As required by Section 650, Special Conditions of the above
referenced project, Traffic and Transporation Supply, Inc. is
providing the following information detailing the Traffic Signal
Equipment offered for use on this project for inclusion with the
contractors' bid.
Per Paragraph 1.22 General Notes, Item 1, TTS is offering the
following equipment for use on this project:
Controller Unit- Multisonics 820A
Conflict Monitor- Eberle Design NSM12L
Loop Detector Amplifier- Detector Systems 813-102SS
Loadswitches- Eberle Design 810
Cabinet- TTS Model PW820A16PAKM128X
Ail of the above equipment will be assembled and tested at our
facility in Fort Worth prior to shipment. All equipment offered
will be in 100% compliance with the project specifications with
no exceptions taken.
Per Paragraph 1.22 General Notes, Item 14, TTS is providing the
following list of Agencies that currently utilize our services
for Signal Maintenance within the Metroplex:
Town of Addison
City of The Colony
City of McKinney
State Department of Highways and Public Transportation Dist. 18.
To aid as a clarification to Addendum Number 1, Item 3, Temporary
Signal installation at Denton Tap Road and Parkway Boulevard, TTS
plans to provide a Controller Cabinet Assembly and Signal Heads
for temporary use until the permanent signal installation is
complete. Pricing for use of this Controller Assembly includes
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the cost of maintenance of the Controller Assembly for the
duration of its use. Due to the fact that utility clearance for
the temporary span is uncertain and clearance above the roadway
is unknown, the signals will be supplied with span wire mounting
hardware for horizontal displays. This will allow the use of a
lower span due to the reduction of the overall height of the
signals.
Bid Alternate #1, #2 and Addendum Number 1, Item 4 reference
modifications to the existing signal at Sandy Lake and Moore
Road. This shall serve to explain and clarify certain details of
this work. Both Alternates for this intersection require the
installation of additional signal sections with dual arrow
indications. In each case, installation of the modified signal
will be made at the approximate mid-point of the span (over the
left lane or left-most thru signal). This will increase the
overall height of the existing signal assembly by appoximately
13" Due to the fact that the existing 3 secion signals have
been struck on previous occasions (due to the low clearance), we
have included with the price of the signal sections, new
horizontal span wire signal mounting hardware for all of the
signals at this intersection. This will allow all signals to be
mounted at a uniform height with additional clearance above the
roadway.
In addition to the signal changes, both alternates require
modifications to the existing 4 phase controller at this
intersection. This is confusing in that the existing controller
is actually a 2 phase controller unit with a 4 phase backpanel
and a 3 channel conflict monitor. In the case of either
alternate, the Controller Unit will have to be upgraded to allow
Multi-phase Operation with a Compatible Backpanel and Conflict
Monitor. In order to perform this modification at the lowest
possible cost to the City, we are including within the bid item
for the Controller Modification, a Multsonics 820A Controller
unit, 8 Position Backpanel, 12 Channel Conflict Monitor, 8
Loadswitches and 4 Transfer Relays. All of this equipment would
be installed in the existing Pole Mounted Controller Cabinet.
This would then eliminate the need to remove the existing
cabinet, relocate the service, relocate the signal conduit, ect..
It also eliminates the unnecessary cost of a controller cabinet
and accessories. As a benefit to this approach, the signal will
be able to operate as a six phase operation (Alternate #1) or as
an eight phase operation (Alternate #2). Due to the multi-phase
approach coupled with the use of the 820A Controller Unit, it
will now be possible to add and remove the protected left turn
signal operation on a time of day basis. It will also be
possible to vary the time allocated to each movement on a time of
day basis and to provide a night flash pattern (a highly
desirable feature due to the limited amount of detection
available). With all factors considered, this approach will
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signifincantly improve the overall operation of this intersection
with a small increase in cost over the specified four phase
operation.
I look forward to working with you on this project and to be of
service in your traffic control needs.
Sincerely,
Richard M. Campbell
President
RMC/sal
coppell