HomeMy WebLinkAbout4.04 TrafficSgnalStdy
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CITY CLERK
File # D~[2]~-@][{2]
AGENDA STATEMENT
CITY COUNCIL MEETING DATE: January 20,1998
SUBJECT:
. Request for Additional Appropriation - Traffic Signal Coordination
Study Capital Improvement Project
Report Prepared by: Lee S. Thompson, Public Works Director
EXHIBITS AlTACHED:
1)
2)
Budget Change Form
Schematic Diagram of Signal System
RECOMMENDATION: ~ Approve additional appropriation in the amount of$17,000 from
unallocated gas tax reserves to CIP #9645
FINANCIAL STATEMENT: The estimated cost for installation of two new master controllers is
$15,000 to $17,000. There would be an ongoing additional telephone cost of approximately $500 per year
for these locations to conununicate with the monitoring computer at the Civic Center.
DESCRIPTION: Beginning in the 1996-97 Fiscal Year and extending into the current
Fiscal Year, the City's traffic engineering consultant, TJKM, has been performing a signal coordination
study that is intended to optimize signal timing on Dublin Boulevard, Amador Valley Boulevard, and San
Ramon Road. The field work for this study has largely been completed, and one of the reconunendations
to come out of the study is that the City's existing interconnected system should be split into three
segments.
Currently, the master controller for the entire system is located at the Dublin Boulevard! San Ramon Road
intersection. When coordination programs are used with a single controller, the cycle length must be set
the same for all intersections. The previous coordinated system, which has not been used for the past two
years, utilized at various times either a 120-second or 107-second cycle length. This was appropriate for
the downtown Dublin Boulevard peak period traffic volume; however, the intersections on Amador Valley
Boulevard and the more easterly portion of Dublin Boulevard did not operate as efficiently as they might
have with a shorter cycle length. This situation was detrimental to side street traffic in the lower-volume
areas, and Staff did receive complaints :from time to time about excessive waiting time for the side streets.
This project proposes to split the system as indicated on the schematic drawing, Exhibit 2, with new master
controllers in two locations. This would allow variations in cycle length for the high-volume westerly
"downtown" segment of Dublin Boulevard versus the lower-volume segment east of Village Parkway, and
would also allow a shorter cycle length on Amador Valley Boulevard. San Ramon Road is proposed to be
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COPIES TO:
TJKM
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coordinated with the Dublin Boulevard system as far as Silvergate Drive, with the more distant Shannon
and Vomac intersections allowed to run "free." TJKM has indicated these two intersections would be
programmed with a longer green time for San Ramon Road to improve traffic flow.
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The work to be performed under the cost estimate noted in the financial Statement above would consist of
purchasing two new master controllers and appurtenant equipment, installing telephone lines to the two
new locations, and modifying the existing interconnect. The equipment cost itself is approximately
$10,000, and Pacific Bell has given Staffa worst-case estimate of $700 per intersection for connection
costs. The balance of the estimated cost is for installing conduit from the controller cabinets to the nearest
Pacific Bell service points and labor to make the necessary connections. This portion of the work is
proposed to be accomplished through the City's contract with Alameda County in order to minimize the
cost as much as possible.
The consequence of not performing this work is that TJKM would make an alternate reconunendation
NOT to coordinate approximately half of the City's traffic signals, which would reduce traffic flow
efficiency. The intent of the coordination program, which is receiving grant funds based on improving air
quality and reducing fuel consumption, would then largely be defeated.
In addition, the current single interconnect is overly long, as it extends nearly two miles along San Ramon
Road, two miles along Dublin Boulevard, over a mile along Amador Valley Boulevard, along Village
Parkway between Amador Valley and Dublin Boulevard, and along Dougherty Road between Dublin
Boulevard and Sierra Lane. This excessive length affects the performance of the system.
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Staffis recommending an additional appropriation at this time rather than waiting for the next fiscal year's
budgeting for two reasons: (1) the coordination project cannot be satisfactorily completed without the
two new master locations, and (2) Staff would prefer to install the telephone conduit for the Dougherty/
Sierra location before the Kragen project paves and!or installs landscaping behind the sidewalk on Sierra
Lane. The estimated timing for Kragen's work is about 30 days.
Staffreconunends that the City Council approve an appropriation in the amount of$17,000 to perform this
work.
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Page 2
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CITY OF DUBLIN
BUDGET CHANGE FORM
CHANGE FORM #
New Appropriations (City Council Approval Required):
Budget Transfers:
X From Unappropriated Reserves From Budgeted Contingent Reserve (1080-799.000)
Within Same Department Activity
From New Revenues Between Departments (City Council Approval Required)
Other
llillillimmmtiiiG"Jftiw~IODWifi~tmI@1_QViTW111MHntli.n.1_1itlitatltiUltQUNlfl#fIllliKMti_1@
Name: Name: Signal Coordination eIP
$17,000
Account #:
Name:
Account #:2Q6..9645-750-050
Name:
Account #:
Name:
Account #:
Name:
Account #:
Account #:
City Manager:
Date:
Signature
REASON fOR BUDGET CHANGE ENTRY:
signal system
To implement recommendation for coordinated traffic
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Mayor:
Date:
Signature
Posted By:
Date:
Signature
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