HomeMy WebLinkAboutMONTAVA - PHASE G & IRRIGATION POND - BDR210013 - SUBMITTAL DOCUMENTS - ROUND 1 - SUPPORTING DOCUMENTATION
kimley-horn.com 3930 East Jones Bridge Rd, Suite 350, Peachtree Corners, GA 30092 (404) 857-4670
December 15, 2021
To:
Nicole L. Hahn, P.E.
City of Fort Collins, CO
626 Linden Street
Fort Collins, CO 80524
From:
Mark Lenters, P.E. (Kimley-Horn and Associates, Inc.)
Jay VonAhsen (Kimley-Horn and Associates, Inc.)
Cc:
Max Moss (HF2M Colorado)
Ruth Rollins, P.E. (Rollins Consult LLC)
Re: Timberline Road and Mountain Vista Drive Proposed Intersection Quantities
Proposed Roundabout and Proposed Traffic Signal
INTERSECTION FEASIBILITY STUDY – QUANTITIES SUMMARY
On October 1, 2021 a Montava Master Planning – Roundabout Feasibility Draft Report was provided to the
City of Fort Collins via email with updated geometric layouts and opinions of probable construction costs
(OPCC) for a proposed traffic signal and a proposed roundabout alternative at the intersection of Timberline
Road and Mountain Vista Drive. The following information summarizes the conceptual level OPCCs
regarding limits of measurement and values assigned to each pay item.
Quantity Limits using Matchlines
Due to the lack of detail in the grading design at the concept stage, the Mountain Vista at N Timberline
OPCC estimates were generated by measuring quantities for pavement removal, proposed pavement,
proposed curb and gutter, and proposed sidewalk within the matchlines shown on Exhibit 1.0 and Exhibit
2.0 within the October 1, 2021 Report. The matchlines help ensure the comparison of traffic signal vs
roundabout alternatives have an apples-to-apples comparison based on the limits used for quantities. The
earthwork item assumes 3ft of excavation/embankment within the matchline limits relative to the existing
topography. Other standard pay item disciplines like illumination, landscaping, utility adjustments, signage,
pavement markings, etc. are factored using a percentage of overall paving construction costs and
compared versus historical roundabout bid costs.
OPC Items and Unit Prices
Typical construction percentage ranges of overall paving costs have been applied to the following
disciplines to develop an overall conceptual level estimate for the Timberline Road at Mountain Vista Drive
OPCCs:
Pavement Markings and Signage items typically account for 2%-5% of the overall bid.
Illumination items typically account for 3%-10% of the overall bid.
Landscaping items typically account for 2%-5% of the overall bid.
Erosion control items typically account for 0.5%-1.5% of the overall bid.
kimley-horn.com 3930 East Jones Bridge Rd, Suite 350, Peachtree Corners, GA 30092 (404) 857-4670
Utility adjustments (minor) typically account for 1%-4% of the overall bid.
Earthwork typically accounts for 3%-5% of the overall bid.
Removal items typically account for 2%-6% of the overall bid.
Roadway paving is quantified per SY with a $110/SY unit price applied. This includes subgrade
prep, subgrade stabilization, and the full-depth pavement section complete in-place.
Traffic control varies depending on full closure, partial closures, or full traffic. Typical ranges for
MOT/Traffic Control is 3%-6% of overall bid.
Drainage items (routine enclosed systems for inlets, pipes, junctions) typically account for 3%-5%
of the overall bid.
ROW documentation and acquisition, construction materials testing, engineering and survey fees
and other non-material and non-labor construction expenses are not included in the OPCC.
It should be noted that the quantities for the proposed drainage structure, the pedestrian/bike underpass
structure, and proposed retaining wall included in the roundabout OPCC are due to the slight increase in
quantities for this scenario. The increase in quantities, compared to the traffic signal alternative, is due to
the wider section of crossing underneath Mountain Vista Dr that the roundabout scenario creates (See
Exhibit 3.0 within the October 1, 2021 Report). The eastbound exit lanes from the roundabout are south of
the typical roadway section lanes due to their transition from the wider circulatory roadway of the
roundabout back to the proposed Mountain Vista Drive lanes. This area where the drainage structure and
pedestrian/bicycle underpass crosses Mountain Vista Drive is approximately 80ft east of the center of
intersection.
The roadway paving item unit price is programmed at $15 more expensive per SY for the roundabout
alternative due to the non-linear material installation and labor required for construction of the roundabout
which tends to create slightly more effort during construction compared to a traditional intersection. The
traffic control item is an additional two months for the roundabout alternative for similar reasons. The
landscaping pay item for the roundabout is also elevated given the typical application of vegetative elements
within the central landscaped island.
Typically, in greenfield construction or retrofit scenarios where an existing intersection is being widened to
accommodate additional lanes, the roundabout alternative is similar in cost if not several hundred-thousand
dollars less costly than a signalized alternative. This is due to two common factors:
1. The omission of traffic signal equipment for the roundabout alternative
2. Slightly less pavement quantity due to the center of the intersection being vegetated instead of
fully paved, although the additional cost for roundabout pavement may offset the reduced quantity