HomeMy WebLinkAboutA025 - August 11, 2026, Regular Meeting of the Ames City CouncilITEM #:25
DEPT:PW
August 11, 2026
Staff Report
UPDATE ON ROUNDABOUT IMPROVEMENTS AT G.W. CARVER AND CAMERON
SCHOOL ROAD
BACKGROUND:
The intersection of G.W. Carver Avenue and Cameron School Road lies along the boundary
between the City of Ames and Story County. The intersection has been identified as a critical
location for future transportation improvements because of current rural commute patterns
and the projected traffic growth associated with planned and approved development in
northwest Ames, including The Bluffs at Dankbar Farms and the proposed Greenbriar
development. This need was first identified with the Dankbar project's traffic study.
Subsequent to the City's annexation and approval of the Dankbar project, the Ames Area
Metropolitan Planning Organization (AAMPO) updated the long-range transportation plan with
planned north growth. The 2050 Metropolitan Transportation Plan (MTP) developed by the
AAMPO identifies that with full buildout of north growth a roundabout at this location,
Project N-47, is the preferred long-term improvement compared with the base
assumption of a traffic signal improvement.
The anticipated roundabout benefits include speed management, improved safety, better
multimodal access, and lower long-term operating and maintenance costs. However, this
project is not included as a short-term project in the fiscally constrained program of the
MTP as it was assumed to be a developer-funded project at the time of the plan's
adoption.
The existing Dankbar development agreement contemplated developer-funded turn-lane
improvements and eventual traffic signalization, not a roundabout. The developer estimated
their turn lane obligations to cost $1.2 million and requested a 10-year TIF rebate as an
incentive for the project.
In December 2025, the City Council supported up to $1 million of TIF rebate over 10 years to
the developer for the lane widening as part of the City's overall housing development
i n c e n t i v e s . The City Council separately directed staff to pursue a roundabout
intersection project with Story County that would be coordinated by the City, not a
developer, in lieu of individual developer-constructed intersection improvements
discussed with the housing incentives.
Funding for the roundabout included assumptions of an Iowa Department of
Transportation (DOT) grant, Story County funding, developer contributions, and the use
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of City funds as incentives related to the Dankbar and Greenbriar projects. A
determination of the funding share related to the Dankbar project was deferred at the
time of The Bluffs Final Plat approval on June 9.
Planning-level estimates at the time of the incentive discussion in December 2025
anticipated that the roundabout and associated corridor improvements would cost
approximately $3 million. Preliminary engineering was required to establish the project
limits, right-of-way impacts, drainage requirements, and a more detailed Opinion of
Probable Construction Cost.
On January 30, 2026, the City of Ames Mayor sent a request to Story County for a partnership
with the City in evaluating the roundabout alternative. Story County approved moving forward
with preliminary engineering on February 10, 2026. On February 24, 2026, the City Council
approved a Memorandum of Understanding (MOU) with Story County.
Under the MOU, the City and County agreed to share equally in the cost of preliminary
engineering and preparation of a Traffic Safety Improvement Program (TSIP) grant
application, with Story County’s participation capped at $50,000. The MOU does not obligate
either party to proceed with final design or construction. On April 28, 2026, the City Council
approved a professional services agreement with Bolton & Menk, Inc. for preliminary design
and preparation of the TSIP application in an amount not to exceed $60,728.
DESIGN ALTERNATIVES:
Attached to this staff report is an appendix that contains more detailed information on the four
design alternatives and associated project cost estimates that were developed by Bolton and
Menk. Only two of the design alternatives are being considered in this report. These two
represent the best technical solutions and are the most practical choices for
addressing the necessary intersection improvements and are presented below:
Design Alternative A: Roundabout
This alternative includes the construction of a single-lane roundabout at G.W. Carver Avenue
and Cameron School Road, together with the associated approach, drainage, pedestrian, and
other supporting improvements. This alternative supports the lower-speed (35 MPH), urban,
and multimodal corridor identified in the AAMPO 2050 Metropolitan Transportation Plan and
addresses the same intersection-improvement need contemplated by the Dankbar
development agreement.
Design Alternative D: Traffic Signal with Lane Widening
This alternative includes installation of a traffic signal and construction of only the necessary
turn lanes while retaining the existing two-lane pavement where practical. The roadway
maintains a higher-speed corridor (45 MPH), but would be widened by approximately one lane
through the rural section. The east leg of the intersection is assumed to require full
reconstruction because of the existing roadway alignment. This alternative represents the
minimum practical signalized improvement and is based on planning-level assumptions for
earthwork and storm sewer needs.
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PROJECT COST ESTIMATES:
City staff reviewed the consultant’s estimated quantities and applied average historical City of
Ames bid prices for the two alternative identified above. For project budgeting, the resulting
construction costs were estimated with a 5% construction contingency applied, and an
additional 20% was included for design and administration.
Design Alternative
Estimated
Construction Expense
(With 5%
Contingency)
Overall Project
Expense
(With 20% Design and
Administration)
Alternative A: Roundabout $3,154,200 $3,785,040
Alternative D: Traffic Signal with Lane
Widening
$2,027,550 $2,433,060
These preliminary estimates do not include permanent right-of-way or temporary easement
acquisition. Any acquisition costs will be identified as the project and adjacent development
plans advance and will be incorporated into the project budget before final design and bidding.
It is estimated that any costs would be nominal and likely less than $5,000. However, any
acquisition from the Dankbar or Greenbriar sites would be at no cost.
PROJECT REVENUES:
The funding amounts shown below are planning assumptions and no funding agreements
have been finalized. The requested $500,000 TSIP grant is applicable only to the roundabout.
The Story County funding amount represents 25% of project costs in Alternative A, after taking
into account grant funding and developer cash contributions. The Story County funding
amount for Alternative D represents 25% of the cost of the traffic signal only. It does not
include any funding associated with the lane widening.
Story County's share is proposed at 25% because one of the four quadrants of the
intersection is located within Story County's jurisdiction. It is important to note that
these amounts are not a commitment and would require an additional funding
agreement with the County. The Story County Board of Supervisors is reviewing the
same roundabout study and cost estimates at its August 11 meeting.
The $200,000 additional developer cash contribution in both Alternative A and D has
been verbally agreed to by the Developer. The remaining developer and projected TIF
amounts remain subject to the applicable development agreements, minimum assessment
agreements, and future City Council action.
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Funding source Roundabout
Alternative
A
Signal –
Widening
Only
Alternative D
Funding Assumption
City ARPA Funding $820,000 $820,000 Previously identified City funding for
Greenbriar Housing Development
Incentive
Iowa DOT TSIP $500,000 $0 Requested for Alternative A, subject
to grant award. Not eligible for
Alternate D.
Previous traffic-signal
contribution
$135,000 $135,000 Assumed available for the
intersection improvement
Additional Developer
cash contribution
$200,000 $200,000 Assumed based off verbal
agreement with Developer
Story County
participation (25% of
project cost)
$738,000 $125,000 Alternative A amount is based on
initial discussions of 25% of the
project cost after grant and cash
contributions. Alternative D is an
assumption based off 25% of the
traffic cost of the signal itself.
Neither option represents
a commitment and would require a
funding agreement with Story
County.
Dankbar Development
TIF Assumption
$1,000,000 $1,000,000 Alternative D reflects the original
lane-widening obligation with a $1
million TIF rebate to developer;
Alternative A reflects the previously
assumed $1 million TIF to the
developer, but instead collected
directly by the City.
SUBTOTAL OF
ASSUMED FUNDING
$3,393,000 $2,280,000
Remaining funding
required
$392,040 $153,060 Additional funding to be finalized
through agreements and/or City
funding. This funding would likely
be from TIF and/or MPO funding
depending upon the option Council
chooses.
Total project funding $3,785,040 $2,433,060
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This preliminary comparison considers only initial project costs and funding
assumptions; it does not account for the alternatives’ ongoing operation and
maintenance costs or the long-term safety benefits associated with the roundabout’s
anticipated crash reduction over the life of the project.
Because several funding sources have not been committed, the final City funding
requirement cannot yet be determined. Any remaining balance after grant, County, TIF-
support, and developer funding is finalized may require General Obligation bonds,
AAMPO funds, or another City funding source. With relatively similar remaining funding
gaps under the current assumptions, the comparison can focus primarily on the long-
term operational, safety, speed-management, multimodal, corridor-character, and
maintenance implications of the two intersection treatments.
TSIP GRANT APPLICATION:
Bolton & Menk has prepared a draft application requesting $500,000 from the Iowa DOT
Traffic Safety Improvement Program (TSIP). The application is based on the Alternative A
roundabout project and identifies the safety-related portion of the construction work. Award of
the grant is evaluated based upon the safety improvements that can be achieved through a
project. The Story County Board of Supervisors is anticipated to provide a letter of support for
the project and TSIP application at its August 11, 2026 meeting. Applications for the TSIP
grant are due on August 15, 2026.
The draft application identifies the following safety benefits:
Conversion of the existing two-way stop-controlled intersection to a single-lane
roundabout.
Reduction in vehicle conflict points from 32 to 8.
Improved speed management at the transition into the developing urban area.
Improved pedestrian and shared-use path crossings.
Continued acceptable operation at Level of Service A under projected traffic volumes.
A projected crash reduction of approximately 65%.
A favorable safety benefit-cost ratio of 2.76.
The analysis estimates that the roundabout would reduce crashes by approximately
65% over its anticipated service life. A benefit-cost ratio of 2.76 means the estimated
present value of the project’s safety benefits is 2.76 times the present value of its
implementation and maintenance costs. A ratio greater than 1.0 indicates that the
estimated benefits exceed the estimated costs.
OPTIONS:
The options below focus on the primary decision of whether the long-term intersection
treatment should be a roundabout or a traffic signal, as well as the timing and funding strategy
for the selected improvement.
OPTION 1: ROUNDABOUT (ALTERNATIVE A):
Under this option, the City Council would select the roundabout as the preferred long-term
intersection treatment and proceed using the preliminary design. The project would establish a
transition from the existing 45 mph corridor to a 35 mph posted-speed environment through
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the corridor.
The current project cost estimate for Alternative A is $3,785,040. Staff would submit the
requested $500,000 TSIP grant application and continue coordinating with Story County
and the affected developers. The funding plan assumes $738,000 of Story County
participation, representing approximately 25% of the estimated project cost less grant
and developer cash funding. This is not a County commitment and would require an
additional funding agreement.
The assumed County, developer, TIF-supported, grant, and City funding amounts would need
to be finalized before the project advances into final design and bidding.
Based on the preliminary funding assumptions, the estimated remaining funding need
is $392,040 that is expected to be funded through the use of TIF by the City from the
development in the abutting Bluffs project.
Once the funding responsibilities are sufficiently defined, staff would return to the City Council
with the proposed funding agreements and a professional services agreement for final design.
Final design is anticipated to begin after July 1, 2027, followed by a potential project
letting in late 2027/early 2028 and construction in 2028. This schedule generally
corresponds with anticipated development along the corridor.
The roundabout would reduce vehicle speeds and eliminate high-speed crossing and
left-turn conflicts. The safety analysis prepared for the TSIP application estimates an
approximately 65% reduction in crashes over the anticipated service life of the
improvement.
The roundabout would operate at Level of Service A under the 2027 and 2050 traffic forecasts
and would support a lower-speed, urban, and multimodal corridor with lower long-term
operating and maintenance requirements than a traffic signal. It is estimated that a
roundabout alternative would save $10,000 - $15,000 annually in operating and future
signal replacement expenses.
OPTION 2: TRAFFIC SIGNAL WITH LANE WIDENING (ALTERNATIVE D):
Under this option, the City Council would not proceed with the roundabout and would instead
select the widening-only traffic signal alternative.
The existing two-lane pavement would generally remain in place, and pavement would be
added where necessary to provide the recommended turn lanes. The widening would be
completed as a developer improvement, with the traffic signal installed at a later date when
traffic conditions and development timing warrant installation.
The Alternative D estimate includes both the roadway widening and the future traffic signal.
The east leg of the intersection is assumed to require reconstruction because of the existing
roadway geometry. Future roadway reconstruction and development-specific improvements
could be completed separately.
The current project cost estimate for Alternative D is $2,433,060. There would be no
TSIP fund because the traffic signal option would not be eligible. Staff would continue
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coordinating with Story County and the affected developers.
One of the four traffic-signal poles would be located within Story County right-of-way,
requiring additional coordination with the County and a request for future financial
participation for 25% of the signal cost amounting to an estimated $125,000 would be
negotiated with Story County.
No Story County funding for widening is included in the current Alternative D funding
assumptions. The widening along G.W. Carver Avenue would be completed as a
developer improvement, and Story County would not participate in the roadway-
widening costs.
Based on the preliminary funding assumptions, the estimated remaining funding need
is $153,060 that is expected to be funded through the use of TIF by the City from the
development in the abutting Bluffs project.
When installed, a traffic signal could provide protected-turn phases and dedicated pedestrian
intervals, but it is not the preferred long-term improvement identified in the AAMPO 2050
Metropolitan Transportation Plan.
The corridor would remain posted at 45 mph and would retain higher-speed crossing
and turning conflicts. The traffic impact and safety analyses indicate negligible crash
reduction from a signal alone and an approximately 25% reduction in crashes when the
recommended left-turn lanes are included, compared with the approximately 65%
reduction estimated for the roundabout.
The preliminary traffic analysis identifies approximately 450 feet between Cameron School
Road and Columbus Drive, which limits the available distance for turn-lane storage and
transitions. Because the turn-lane improvements would extend through the Columbus Drive
intersection, Columbus Drive may need to be converted to right-in/right-out access, requiring
left-turning traffic to use alternate routes.
The 45 mph design would require longer roadway taper transitions, retain a more
suburban corridor character, and make comfortable pedestrian and bicycle crossings
more difficult. A traffic signal would also require ongoing electrical service, equipment
maintenance, and periodic replacement.
OPTION 3: ROUNDABOUT ALTERNATIVE A BUT DEFER THE PROJECT, REQUEST TO
AMEND THE AAMPO METROPOLITAN TRANSPORTATION PLAN, AND PURSUE
AAMPO STBG FUNDING IN FFY 2034 OR LATER:
Under this option, the City Council would select the roundabout as the preferred long-term
intersection treatment, but delay final design and construction until federal-aid funding may
become available through AAMPO's Surface Transportation Block Grant (STBG) program.
Based on current AAMPO funding forecasts and the projects anticipated to compete for
those funds, FFY 2034 (October 2033–September 2034) is the earliest year STBG
funding could reasonably be expected.
The project would be programmed in the Capital Improvements Plan accordingly, and the
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corridor would remain posted at 45 mph until the roundabout is constructed. Staff would also
continue to protect the anticipated roundabout footprint through development agreements,
access decisions, right-of-way dedication, and easement coordination prior to construction.
Securing STBG funding would require two separate AAMPO actions, neither of which
can be guaranteed. First, although the adopted AAMPO 2050 Metropolitan Transportation
Plan (MTP) identifies the roundabout, Project N-47, as the preferred long-term improvement,
the project is not included in the MTP's fiscally constrained program because it was assumed
to be developer funded. AAMPO would need to amend the MTP to include the project as a
short-term improvement within the fiscally constrained program before it would be
eligible for STBG funding.
Second, an MTP amendment alone does not provide funding. The project would also need
to be submitted through AAMPO's annual competitive STBG application cycle, selected
for award over other regional projects, and programmed in the Transportation
Improvement Program (TIP).
Because the intersection lies on the boundary between the City of Ames and Story
County and both jurisdictions have authority over portions of it, the City and County
would need to submit a joint STBG application. This would require a funding agreement
between the two jurisdictions in advance of the application, including designation of
the lead agency for federal-aid project delivery.
Deferral would also increase the cost of the improvement. Applying 3% annual inflation over
eight years to the current $3,785,040 planning-level estimate results in an estimated
2034 project cost of approximately $4,795,000. This estimate would need to be reevaluated
as development conditions and project requirements change.
An STBG award would require a 20% local match, consistent with AAMPO's standard 80/20
federal/local split. Against the escalated estimate, the local share for construction would be
approximately $959,000. Because the Iowa DOT Traffic Safety Improvement Program is a
state rather than federal program, a TSIP award could be applied toward that match.
However, the City should not assume a 2026 TSIP award could be retained until
construction in 2034. A new application would likely be required at the appropriate
point in the modified schedule, with no assurance of award. In this option staff would
not recommend applying for the TSIP grant in 2026, but rather wait until the project is
closer to construction.
This option would require a substantially different funding strategy from Option 1, and
the $392,040 remaining funding need shown for Alternative A does not apply. The
project would rely primarily on future STBG funding and the required local match, and would
likely not include the currently assumed TIF-supported funding. The amount and source of the
local match, including any future City or County participation, would be determined when the
project is programmed.
Before final design begins, staff would reevaluate traffic conditions, adjacent development,
and project limits, and would identify any interim improvements needed to accommodate
traffic growth in the meantime. This option retains the long-term safety, speed-
management, multimodal, and corridor-character benefits of the roundabout, but
delays those benefits (and the capacity improvements needed to serve area growth)
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until construction is complete.
The project delay comes with an increased cost in the improvement and would
reallocate funding that is typically used for street reconstruction projects in the City of
Ames CIP.
STAFF COMMENTS:
Option 1 presents the best solution to advance the intersection improvement while the
surrounding area is developing. It is consistent with the AAMPO 2050 Metropolitan
Transportation Plan, and provides the roundabout’s anticipated safety, speed-management,
and multimodal benefits on the earliest schedule. Option 1 also takes advantage of TSIP grant
funding to help fund the improvements.
Under Option 1, staff will finalize the TSIP application and submit it to the Iowa DOT by
the August 2026 deadline. Submission of the application would not authorize final
design, property acquisition, bidding, or construction. It would preserve the City’s
opportunity to obtain up to $500,000 in state safety funding while the remaining project
funding, cost allocations, and responsibilities are finalized.
Option 1 also requires that finalized developer agreements and TIF agreements are
successfully negotiated in order to provide the necessary revenues to fund the project.
Option 1 is contingent upon agreements between Story County and the City of Ames for
25% of the cost as shown. Story County's share is proposed at 25% because the one of
the four quadrants of the intersection is located within Story County's jurisdiction. Staff
has requested through consultation with the County Engineer that the Board of
Supervisors address at their August 11th meeting the assumed funding participation
and whether to proceed with the TSIP application consistent with these assumptions.
With this option and Story County's concurrence, the City would apply for the state
grant by August 15, 2026. Staff will return to the City Council with the proposed funding plan,
cost allocations, intergovernmental and development agreements, and professional services
agreement for approval before entering into final design or otherwise committing the City to
construct the project.
If the Story County Board of Supervisors, at its August 11 meeting, does not support
the TSIP application or indicates that the County's funding participation percentage
would be less than the 25% in the table above, there would not be adequate funding to
support the roundabout construction as noted in Option 1.
In this scenario, staff would recommend that the City Council chose Option 2 which
would widen the existing pavement and install a traffic signal in lieu of the roundabout.
No application would be made regarding TSIP grant funding as it is not eligible to fund
a traffic signal improvement at this location.
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ATTACHMENT(S):
Roundabout PRELIMINARY DESIGN FIGURE
ROW Figure
TSIP - Benefit Cost Estimate
GW Carver Report Design Alternatives.pdf
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GEORGE WASHINGTON CARVER AVENUE AND CAMERON SCHOOL ROAD INTERSECTION IMPROVEMENTS
CITY OF AMES, IA
PRELIMINARY DESIGN
JULY 2026
PLAN LEGEND
ROADWAY
MEDIAN
SIDEWALK/TRAIL
TRUCK APRON
DRIVEWAY PAVEMENT
AGGREGATE SHOULDER
TURF/LANDSCAPING
THE BLUFFS DEVELOPMENT
GREEN BRIAR DEVELOPMENT
DOVER DEVELOPMENT
EXISTING ROW/ESMT/PARCELS
PROPOSED ROW/ESMT
TEMPORARY ESMT
CONSTRUCTION LIMITS
CITY OF AMES LIMITS
R
FEETSCALE
0 75 150
ALTERNATIVE B
ALTERNATIVE A
GEORGE WASHINGTON CARVER AVENUE
CA
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EVEREST AVENUE
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IRONS COURT
11
1
WEYDERT, JAMIE A & CHRISTINE J
0520200455
2
CHRIST COMMUNITY CHURCH
0520200405
3
CLEMMONS, EDWARD J & THERESA A
0521320060
4
LI, LU
0521320050
5
GILLEN, GARRETT & SARAH
0521320040
6
SPAETTI, CORY & KIM
0521320030
7
FREEMAN, KYLE S & BRITTANY R
0521320020
8
GEMIENHARDT-CESLER, STACY
0521320010
9
ABELL, RANDY & DENNA
0521320140
10
GREEN BRIAR DEVELOPMENT
0521300105
10
GREEN BRIAR DEVELOPMENT
0521300105
11
MANDERNACH, JORDAN & STEPHANIE
0521300150
13
THE BLUFFS/DOVER DEVELOPMENT
0520400008
13
THE BLUFFS/DOVER DEVELOPMENT
0520400008
14
THE BLUFFS DEVELOPMENT
0520400001
15
THE BLUFFS DEVELOPMENT
0520400011
16
COFFIN, DONALD
0520400215
17
JAMISON, DAVID D & KAREN A
0520400210
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GEORGE WASHINGTON CARVER AVENUE AND CAMERON SCHOOL ROAD INTERSECTION IMPROVEMENTS
CITY OF AMES, IA
FIGURE 1: OVERVIEW & SUMMARY
JUNE 2026
FEETSCALE
0 100 200
R
LEGEND
SURVEYED LANDMARK
EXISTING ROW (SURVEYED)
EXISTING ROW (GIS)
EXISTING EASEMENT
EXISTING PARCEL LINE
FUTURE DEVELOPMENT ROW
FUTURE DEVELOPMENT EASEMENT
FUTURE DEVELOPMENT PARCEL LINE
CITY OF AMES CORPORATE LIMITS
SECTION LINE
CONSTRUCTION LIMITS
TEMPORARY EASEMENT
PERMANENT EASEMENT
PERMANENT FEE/ROW
COLUMBUS DR
CAMERON SCHOOL RD
STA
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TABULATION OF EASEMENTS (SUMMARY)
PROPERTY
NO.PARCEL ID OWNER
TEMPORARY
EASEMENT
PERMANENT
EASEMENT
PERMANENT
FEE/ROW
(S.F.)(S.F.)(S.F.)
1 0520200455 WEYDERT, JAMIE A & CHRISTINE J ---
2 0520200405 CHRIST COMMUNITY CHURCH 21,238 762 -
3 0521320060 CLEMMONS, EDWARD J & THERESA A ---
4 0521320050 LI, LU ---
5 0521320040 GILLEN, GARRETT & SARAH ---
6 0521320030 SPAETTI, CORY & KIM ---
7 0521320020 FREEMAN, KYLE S & BRITTANY R ---
8 0521320010 GEMIENHARDT-CELSER, STACY ---
9 0521320140 ABELL, RANDY & DENNA ---
10 0521300105 GREEN BRIAR DEVELOPMENT 11,412 362 6,432
11 0521300150 MANDERNACH, JORDAN & STEPHANIE 400 --
12 0520400420 HILKER, RICK A ---
13 0520400008 THE BLUFFS/DOVER DEVELOPMENT 23,843 3,330 1,366
14 0520400001 THE BLUFFS DEVELOPMENT ---
15 0520400011 THE BLUFFS DEVELOPMENT 125 --
16 0520400215 COFFIN, DONALD ---
17 0520400210 JAMISON, DAVID D & KAREN A ---
TOTAL:57,018 4,454 7,798
JULY 2026
12
2
CHRIST COMMUNITY CHURCH
0520200405
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GEORGE WASHINGTON CARVER AVENUE AND CAMERON SCHOOL ROAD INTERSECTION IMPROVEMENTS
CITY OF AMES, IA
FIGURE 2: WEST OF ROUNDABOUT
JUNE 2026
FEETSCALE
0 30 60
R
LEGEND
SURVEYED LANDMARK
EXISTING ROW (SURVEYED)
EXISTING ROW (GIS)
EXISTING EASEMENT
EXISTING PARCEL LINE
FUTURE DEVELOPMENT ROW
FUTURE DEVELOPMENT EASEMENT
FUTURE DEVELOPMENT PARCEL LINE
CITY OF AMES CORPORATE LIMITS
SECTION LINE
CONSTRUCTION LIMITS
TEMPORARY EASEMENT
PERMANENT EASEMENT
PERMANENT FEE/ROW
6,250 S.F.
CAMERON SCHOOL RD
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25'
35'
61
'
45
0
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50
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50
'
125'
14,988 S.F.
762 S.F.
TABULATION OF EASEMENTS
PROPERTY
NO.PARCEL ID OWNER
TEMPORARY
EASEMENT
PERMANENT
EASEMENT
PERMANENT
FEE/ROW
(S.F.)(S.F.)(S.F.)
2 0520200405 CHRIST COMMUNITY CHURCH 21,238 762 -
TOTAL:21,238 762 0
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GREEN BRIAR DEVELOPMENT
0521300105
10
GREEN BRIAR DEVELOPMENT
0521300105
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MANDERNACH, JORDAN & STEPHANIE
0521300150
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GEORGE WASHINGTON CARVER AVENUE AND CAMERON SCHOOL ROAD INTERSECTION IMPROVEMENTS
CITY OF AMES, IA
FIGURE 3: WEST OF ROUNDABOUT
JUNE 2026
FEETSCALE
0 30 60
R
LEGEND
SURVEYED LANDMARK
EXISTING ROW (SURVEYED)
EXISTING ROW (GIS)
EXISTING EASEMENT
EXISTING PARCEL LINE
FUTURE DEVELOPMENT ROW
FUTURE DEVELOPMENT EASEMENT
FUTURE DEVELOPMENT PARCEL LINE
CITY OF AMES CORPORATE LIMITS
SECTION LINE
CONSTRUCTION LIMITS
TEMPORARY EASEMENT
PERMANENT EASEMENT
PERMANENT FEE/ROW
35'
4,192 S.F.
CA
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GEORGE WASHINGTON CARVER AVE
40'
10
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10
'400 S.F.7,220 S.F.362 S.F.
6,432 S.F.15
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10'
10'
27
1
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3
'
65.61'
TABULATION OF EASEMENTS
PROPERTY
NO.PARCEL ID OWNER
TEMPORARY
EASEMENT
PERMANENT
EASEMENT
PERMANENT
FEE/ROW
(S.F.)(S.F.)(S.F.)
10 0521300105 GREEN BRIAR DEVELOPMENT 11,412 362 6,432
11 0521300150 MANDERNACH, JORDAN & STEPHANIE 400 --
TOTAL:11,412 362 6,432
14
13
THE BLUFFS/DOVER DEVELOPMENT
0520400008 13
THE BLUFFS/DOVER DEVELOPMENT
0520400008
14
THE BLUFFS DEVELOPMENT
0520400001
15
THE BLUFFS DEVELOPMENT
0520400011
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GEORGE WASHINGTON CARVER AVENUE AND CAMERON SCHOOL ROAD INTERSECTION IMPROVEMENTS
CITY OF AMES, IA
FIGURE 4: SOUTH OF ROUNDABOUT
JUNE 2026
FEETSCALE
0 40 80
R
LEGEND
SURVEYED LANDMARK
EXISTING ROW (SURVEYED)
EXISTING ROW (GIS)
EXISTING EASEMENT
EXISTING PARCEL LINE
FUTURE DEVELOPMENT ROW
FUTURE DEVELOPMENT EASEMENT
FUTURE DEVELOPMENT PARCEL LINE
CITY OF AMES CORPORATE LIMITS
SECTION LINE
CONSTRUCTION LIMITS
TEMPORARY EASEMENT
PERMANENT EASEMENT
PERMANENT FEE/ROW
125 S.F.
GEORGE WASHINGTON CARVER AVE
TABULATION OF EASEMENTS
PROPERTY
NO.PARCEL ID OWNER
TEMPORARY
EASEMENT
PERMANENT
EASEMENT
PERMANENT
FEE/ROW
(S.F.)(S.F.)(S.F.)
13 0520400008 THE BLUFFS/DOVER DEVELOPMENT 20,476 3,330 1,366
15 0520400011 THE BLUFFS DEVELOPMENT 125 --
TOTAL:20,476 3,330 1,366
10
'
525'
15
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25'
16'52.84'
17
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8
'
30'
5'
5'
25'
25'
25
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5,250 S.F.18,593 S.F.
3,330 S.F.
1,366 S.F.
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EVEREST AVE
10'
15
Attachment L: Safety Benefit-Cost Ratio
County: Story Prepared By:
Location: Date Prepared:
Proposed Improvements:
Estimated Improvement Cost: 1,958,000$
Inflation on Crash Costs: 4%
Discount Rate: 4%
Estimated Service Life: 25 Annual Maintenance Cost:
Method Choice:
Predictive Method
Existing Condition (All Crashes): 45.33 Location Characteristics:
Alternative (All Crashes): 15.87
Percent Change in Crashes 64.99% reduction in crashes Iowa Crash Distribution 2017-2021
Crash Severity
Crash
Distribution
Based on
Location
Characteristics
Existing
Condition
Expected
Crashes -
Service Life
Alternative
Expected
Crashes -
Service Life
Crashes Saved
Over Service
Life
Crashes Saved
Annually
Fatal (K) 1.45% 0.66 0.23 0.43 0.02
Serious Injury (A) 5.18% 2.35 0.82 1.53 0.06
Minor Injury (B) 15.60% 7.07 2.48 4.60 0.18
Possible/Unknown Injury (C) 19.12% 8.67 3.03 5.63 0.23
Property Damage Only (O) 58.65% 26.59 9.31 17.28 0.69
Crash Severity
Rounded
Societal Costs
Annual Societal
Benefit
Fatal (K) 4,500,000$ 77,037$
Serious Injury (A) 4,500,000$ 274,704$
Minor Injury (B) 300,000$ 55,141$
Possible/Unknown Injury (C) 145,000$ 32,670$
Property Damage Only (O) 20,000$ 13,822$
Total Benefits and Costs
1,958,000$
611,761$
Present Value Benefits
(Societal Benefits)7,082,654$ 2,569,761$
Present Value Net Return 4,512,894$
Benefit Cost Ratio 2.76 Form continues on next page
Implementation Cost
Present Value of Maint.
Present Value Costs
(Impl. and Maint. Costs)
Rural
Intersections Only
BMI
GWC Ave & Cameron School Rd 7/14/2026
Single-Lane Roundabout
Annual Maintenance:
(% of Improvement Cost)
2%
39,160$
Predictive Method
The Predictive Method uses the outputs from the Highway Safety Manual's Predicted or Expected crash
tool. That tool accounts for changing risk due to increased traffic volumes, so a growth factor is not used
in these calculations. For additional information, click the "Learn More" button.
Version 1.1
Page 1 of 2Version: Crash costs escalated from 2018 16
Attachment L: Safety Benefit-Cost Ratio
County: Story Prepared By:
Location: Date Prepared:
BMI
GWC Ave & Cameron School Rd 7/14/2026
No Input Necessary - No Custom Values In Use
General Customizations
No change to Crash Costs
No change to Discount Rate
No change to Maintenance
Costs
Method-Specific Customizations
Predictive Method in this tool
does not use or customize Crash
History or Traffic Growth Factor.
Version 1.1
Page 2 of 2Version: Crash costs escalated from 2018 17
G.W. CARVER AND CAMERON SCHOOL ROAD DESIGN ALTERNATIVES AND
COST ESTIMATES:
Bolton & Menk has developed preliminary layouts and cost estimates for a roundabout
with or with an extended three lane section south of roundabout. The roundabout design
is preferred due to safety improvements related to speed control. The roundabout is
designed for a 35 MPH travel speed compared to rural highway design speed of 45
MPH.
At the City’s request, the consultant also prepared planning-level cost estimates for two
signalized intersection configurations using the same general project limits. The four
alternatives are described below:
• Alternative A – Roundabout: Construction of a single-lane roundabout at G.W.
Carver Avenue and Cameron School Road, together with the associated
approach, drainage, pedestrian, and other supporting improvements.
This alternative addresses the same intersection-improvement need
contemplated by the Dankbar development agreement, but as a City-led public
project undertaken in partnership with Story County.
Alternative A would have the City construct the roundabout and associated
approach improvements as a partnership project between Story County and the
City of Ames, supporting the lower-speed (35 MPH), urban, and multimodal
corridor identified in the AAMPO 2050 Metropolitan Transportation Plan.
• Alternative B – Roundabout with South Three-Lane Extension: Construction
of all improvements included in Alternative A, plus extension of the three-lane
roadway section farther south of Columbus Drive.
The additional improvements would accommodate the planned Dover Senior
Living driveway connection and support additional development south of the
G.W. Carver Avenue and Cameron School Road intersection.
Including those additional improvements would add development -specific costs
that are not necessary to decide the preferred long-term intersection treatment.
Those improvements and their additional funding responsibilities can be
addressed separately through the developer agreement process, which is
pending for Dover as a condition of driveway approval.
• Alternative C – Traffic Signal with Full Reconstruction: Installation of a traffic
signal and construction of the necessary turn lanes using the same general
project limits as Alternative A.
This alternative assumes that the existing pavement would be removed and
18
reconstructed, with the proposed roadway remaining an urban section with curb
and associated drainage improvements. This alternative provides a more
comparable construction scope to the roundabout alternatives, but would remove
existing pavement that still has useful service life.
Alternative C is full reconstruction of the intersection and approaches to widen
the road and install a signal for a design speed of 45 MPH. The reconstruction
would replace the existing two-lane pavement that in some places still retains
useful service life, making removal and replacement of those areas much more
expensive than simply widening the roadway. Some improvements, including one
signal, would be within the County. If a signal option is selected, widening the
existing roadway where necessary represents the more practical initial
implementation strategy than full reconstruction.
• Alternative D – Traffic Signal with Widening Only: Installation of a traffic
signal and construction of only the necessary turn lanes while retaining the
existing two-lane pavement where practical. The roadway would be widened by
approximately one lane through the rural section, although the east leg of t he
intersection is assumed to require full reconstruction because of the existing
roadway alignment.
This alternative represents the minimum practical signalized improvement and is
based on planning-level assumptions for earthwork and storm sewer needs.
Alternative D would retain the existing two-lane pavement where practical, add
pavement as needed for turn lanes, and install a traffic signal at a later date while
maintaining a higher-speed corridor design with a posted speed limit of 45 MPH.
This option can be completed incrementally compared to the other options.
Unlike the roundabout alternative, the traffic signal alternative would likely
be primarily funded through City of Ames and developer participation
without state grant funds.
PROJECT COST ESTIMATES:
City staff reviewed the consultant’s estimated quantities and applied average historical
City of Ames bid prices. For project budgeting, the resulting construction costs were
estimated with a 5% construction contingency applied, and an additional 20% was
included for design and administration.
19
Design Alternative
Estimated
Construction
Expense
(With 5%
Contingency)
Overall Project
Expense
(With 20% Design
and Administration)
Alternative A: Roundabout $3,154,200 $3,785,040
Alternative B: Roundabout –
With Dover driveway access
$3,390,450 $4,068,540
Alternative C: Traffic Signal –
Full Reconstruction
$3,010,350 $3,612,420
Alternative D: Traffic Signal –
Widening Only
$2,027,550 $2,433,060
These preliminary estimates do not include permanent right -of-way or temporary
easement acquisition. Any acquisition costs will be identified as the project and adjacent
development plans advance and will be incorporated into the project budget before fina l
design and bidding. However, any acquisition from the Dankbar or Greenbriar sites
would be at no cost. No permanent easements or ROW are expected north of the
Cameron School Road intersection.
20