HomeMy WebLinkAboutA4. Baxter and Davis
Commission Memorandum
REPORT TO: Honorable Mayor and City Commission
FROM: Bob Murray, Project Engineer
Rick Hixson, City Engineer
SUBJECT: Baxter/Davis Intersection Improvements
MEETING DATE: April 13th, 2015
AGENDA ITEM TYPE: Action
RECOMMENDED MOTION: Having considered the information provided in written and
presented materials, I move to approve the installation of a signal at the intersection of Baxter and Davis and authorize an increase of the project budget to $1,125,000 in street impact fees and
$725,000 in community transportation (local share) funds, to be incorporated into the Fiscal Year
2016 (FY16) City Manager’s Recommended Budget.
BACKGROUND: The intersection of Baxter Lane and Davis Lane is operating at a failing
level of service during peak traffic hours. This situation will continue to degrade as the surrounding properties continue to develop. The intersection was included in the FY 15 budget
for improvements to correct the level of service deficiencies. A request for proposals for
engineering services was issued, and the firm of Robert Peccia and Associates (RPA) was chosen
to complete the design of the improvements to the intersection. The current contract is for the
pre-design services which is to compare the installation of a roundabout versus a signal for the intersection control.
As part of this effort, RPA completed a Traffic Engineering Report for the intersection which
included the projected traffic from all of the proposed developments that will impact the
intersection. These traffic projections were then used to complete schematic layouts of the minimum improvements required for each option. Finally, cost estimates were completed for
each option. The report, schematics and estimates are attached. Ultimately, the report concludes
that either option will adequately handle future projected traffic. RPA is will present their
findings including simulations of both options showing the operational characteristics of each for
final selection by the Commission.
The estimate for a signal is $1,857,043 and for a roundabout $2,678,916. The FY 15 budget
included $1,250,000 for this work comprised of $750,000 in impact fees and $500,000 from the
community transportation (local share) funds. Higher costs estimates for this intersection are
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primarily due to the large amount of road improvements that need to be completed as part of the
project. Currently the east leg in only constructed to a county road standard and will have to be
completely replaced to provide the structural road section necessary to withstand the anticipated
traffic. Similarly, only half of the roadway is constructed on the north leg. The east half of this leg will need to be entirely constructed with the project including tapers back to the existing
roadway. The majority of the south and west legs can be used as currently configured for the
signal option. The entire intersection will need to be removed and replaced for the roundabout
option resulting in higher capital costs for the roundabout. Another reason for the higher
roundabout costs is the need to install pedestrian signals on all of the legs (see discussion below). Engineering staff is recommending the signal option due to the lower capital costs as well as the
necessity to install the pedestrian signals on all legs of the roundabout.
DESIGN AND FUNDING ISSUES:
A presentation was made to the Impact Fee Advisory Committee on the pre-design report and
budgetary implications. A number questions and issues were raised during that discussion that
staff was asked to address during the Commission meeting. The following is a summary of those
items.
Pedestrian Signals on the Roundabout
The 1990 American with Disabilities Act (ADA) ensures that public facilities are accessible to
people with disabilities. Under the ADA, the Access Board developed design guidelines to
establish minimum requirements known as the ADA Accessibility Guidelines (ADAAG) in 1991.
Additional guidelines were necessary to cover unique situations within public rights-of-way,
such as blind pedestrian and wheelchair street crossings. So in 2002 the Access Board released
Draft Public Rights-Of-Way Accessibility Guidelines (PROWAG) based on recommended best practices developed by advisory committees consisting of disability organizations, public works
departments, transportation officials, engineering groups, and federal and state agencies. After
incorporating public comments, a Revised Draft PROWAG was issued in 2005. The Proposed
PROWAG was published in 2011, titled the “Proposed Accessibility Guidelines for Pedestrian
Facilities in the Publics Right-of-Way”. An update was issued in 2013 for shared-use paths. Once guidelines are adopted by the U.S. Department of Justice (DOJ) and the U.S. Department
of Transportation (DOT), PROWAG will serve as enforceable standards under ADA. However,
the Federal Highway Administration has issued guidance that PROWAG is currently
recommended as best practices.
PROWAG guidelines require pedestrian signals at roundabouts where pedestrians cross more
than one lane. (R306.3.2). Pedestrian signals would not be required on single lane legs at
roundabouts. The continuous traffic flow at multi-lane roundabout legs removes many audible
cues used by blind pedestrians to cross streets. The pedestrian signal allows the visually impaired
to safely cross two lanes or more of traffic by stopping traffic.
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Due to the widespread acceptance of PROWAG, and the pending adoption by the DOJ and DOT,
many states and municipalities are formally adopting PROWAG as design requirements. The
Montana Department of Transportation (MDT) adopted the use of the PROWAG in August 2010
for all projects within MDT’s right-of-way. MDT is currently installing pedestrian signals at the new Belgrade Interchange roundabouts.
The Transportation Research Board is currently conducting research projects for crossing
solutions at roundabouts (NCHRP-3-78B). A draft report is expected in June 2015.
CIP Estimate versus Current Pre-design Estimate
This intersection is included in the FY15 Impact Fee CIP at $750,000. Prior to the current
(FY16 to FY20) CIP, this was the value that was placed on every intersection control project.
Budget estimates have been increased in the current CIP to $990,000 for intersection projects going forward. These values are the 60% share of the project cost that is impact fee eligible.
Given that, the overall project estimated cost used in the CIP is $1,250,000 and $1,650,000
respectively. These estimates are used for every intersection and over the range of projects staff
believes this average cost will be representative. However, costs will vary between individual
projects. Because it is an intersection of two arterials with significant road improvements necessary to two legs, Baxter/Davis is over the estimate used in the CIP. The recently completed
Broadway/Main intersection had very little necessary road improvements and was competed for
an overall project cost of approximately $307,000. More detailed and accurate project by project
cost estimates would require pre-design analysis on every intersection in the CIP that included
traffic impact analyses, conceptual layout of the options, selection of the preferred alternative and completion of detailed estimate. In addition, construction costs are always difficult to
estimate in a rapidly growing community with a limited contractor base.
Required Right of Way Acquisition
Additional right of way will be needed regardless of the option chosen. The property on the northeast corner of the intersection is not annexed and therefore, has not provided the basic right
of way needed for the two upgrade options. No acquisition will be required on the southeast
corner. This property just received preliminary plat approval and had a condition requiring
dedication of whatever right of way is needed for the alternative that is chosen. The properties on the north and southwest corners were annexed many years ago and provided the right of way for the arterial sections, but did not provide any additional at the corners to cover intersection
improvements. If the signal is chosen, there will be a small amount needed in the north and
southwest corners for the installation of the poles and appurtenances. If the roundabout option is
chosen, it is a much larger impact to these corners. This is because the roundabout has a larger footprint and also because the roundabout will need to be offset to the south and west to avoid butting right up against the existing house in the northeast corner. Overall, the roundabout
option would require just under twice the amount of additional right of way based on preliminary
estimates. The costs of the right of way are not included in the estimates. It will be paid for
from a separate CIP item for right of way acquisition. A decision on the intersection option is necessary to proceed with right of way acquisition.
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UNRESOLVED ISSUES: Selection of the Signal or Roundabout Option for intersection
control. Potential delay of future intersection upgrades due to insufficient community
transportation funds.
ALTERNATIVES: Do Nothing, Choose the Roundabout Option,
FISCAL EFFECTS: If the signal option is chosen, the budget will need to be increased to
$1,125,000 from the Street Impact Fee Fund and $725,000 from the community transportation
fund or some other source of local funds. If the community transportation fund as currently
established is utilized, the FY15 allocation of $445,000 (equal to 5 mills) will need to be
augmented with funds from FY16 to provide sufficient funds. Improvements of future intersections may be delayed as a result of insufficient local share. For the roundabout, it would
need to be $1,600,000 from Street Impact Fee Fund, and $1,100,000 from the community
transportation fund.
Given the fact that the current budget authorization will provide enough funding for any likely FY15 costs, both of these increased amounts could be incorporated into the upcoming FY16 City Manager’s Recommended Budget for Street Impact Fee and the Community
Transportation Fund expenditures. It is important to note that proceeding will commit
FY16 dollars to this project.
Attachments: Traffic Engineering Report, Signal Option Exhibit and Estimate, Roundabout Option Exhibit and Estimate
Report compiled on: 4/6/15
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