HomeMy WebLinkAboutAgenda 08_SD-20-40_500 Old Farm_OBrien Eastview_PP
575 Dorset Street South Burlington, VT 05403 tel 802.846.4106 fax 802.846.4101 www.sburl.com
TO: South Burlington Development Review Board
FROM: Marla Keene, Development Review Planner
SUBJECT: SD-20-40 500 Old Farm Road Preliminary Plat Application
DATE: July 20, 2021 Development Review Board meeting
O’Brien Eastview, LLC has submitted preliminary plat application #SD-20-40 to create a planned unit
development of six existing parcels currently developed with three single family homes and a barn and totaling
102.6 acres. The development is to consist of 135 homes in single family, duplex, and three-family dwellings on
nine (9) lots totaling 21.8 acres, nineteen (19) commercial development lots totaling 44.0 acres, one existing
single family home, and 25.1 acres of undeveloped open space, 500 Old Farm Road.
The Board reviewed the application on February 17, March 16, April 20, May 18, and May 26, 2021. They
conducted a field visit on July 6, 2021. The hearing was continued to this, the July 20 meeting, to complete
review of two outstanding topics, plus any additional topics the Board feels they need more information on
prior to closing this preliminary plat hearing.
A) Bicycle/Pedestrian accommodations on Old Farm Road
Since the first meeting, the Board has engaged with the applicant in a discussion of pedestrian connectivity
between the southern terminus of the project and the Hinesburg Road / Tilley Drive area. The applicant
testified on May 18 that they would like to conclude discussion of this connectivity prior to conclusion of the
preliminary plat.
The applicant’s plans show a recreation path from Kimball Ave to O’Brien Farm Road, a sidewalk from O’Brien
Farm Road to Legacy Road, and, based on concerns expressed in previous meetings and outlined herein,
“Advisory Bicycle Lanes” south of that point.
The applicant’s initial traffic study recommended intersection widening at various project intersections,
including Kimball Ave at Kennedy Drive and Old Farm Road, Hinesburg Road at Old Farm Road, and signal
upgrades at three intersections on Williston Road, two on Kennedy Drive, and one on Kimball Ave. Staff’s
recommendation, which neither the Board nor the applicant objected to, was to re-envision the transportation
plan for this project to reflect a multimodal approach, taking into consideration the various policy documents
summarized below, with the objective of reducing the need for expanded roadways by reducing the portion of
trips occurring by motor vehicle.
Policy Documents supportive of Multimodal Strategies
1. VT 116 / Kimball Avenue / Tilley Drive Area Land Use & Transportation Plan – November 2020
This study was commissioned by the City and is being used by the Planning Commission and City
Council regarding prioritization of transportation system upgrades in the vicinity of the project. It
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recommends a shared use path along the entire length of Old Farm Road to meet future demands
on the City transportation network.
2. O’Brien Eastview, LLC Development & Phase 2 of Hillside Development – Responses to questions
to Bicycle and Pedestrian Committee from the DRB 1/29/2021
City Staff formulated a number of questions for the Bike/Ped committee, including this question:
“Staff request committee feedback on the proposed recreation path locations. Are the
proposed locations appropriate? Are there any missing? Are there any locations in which there
should be lanes instead of or in addition to paths? “
The Committee provided a thorough response, provided in the 2/17 packet for the Board, including
the following relevant excerpt:
At minimum, there should be a sidewalk on the west side of Old Farm Road down to Hinesburg
Road from where the currently proposed sidewalk across from the resident recreation/pool area
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ends. As noted below, the Committee would prefer that a shared use path be constructed on the
full length of Old Farm Road.
3. Memorandum “Bicycle/Pedestrian connection to Hinesburg Road from the O’Brien
Development,” prepared by the South Burlington Bike and Pedestrian Committee, dated May 24,
2021
The South Burlington Bicycle and Pedestrian Committee reviewed the various options being
discussed to provide bike and pedestrian connectivity between the O’Brien development, along Old
Farm Road south to Hinesburg Rd. We have listened to and considered the concerns raised by the
developers and several residents on Old Farm Road.
It is the opinion of the South Burlington Bicycle and Pedestrian Committee that the best alternative,
and the one we are recommending, is to place the shared-use path on the east side of Old Farm
Road. Furthermore, we recommend that this section of path starting at Old Meadow Loop be
connected down to Hinesburg Road and south to the end of the existing shared-use path in front of
Red Barn Deli, at 47 Tilley Drive.
The key reasons we support this alternative over the proposed connection from the O’Brien
Development to Tilley Drive along a new industrial road are as follows:
• The grade along Old Farm Road is more gradual and conducive to walking and biking compared
with the Tilley Drive alternative.
• The connection along Old Farm Road is significantly more direct, both for residents of the new
O’Brien development as well as commuters moving through the area.
• We think that walking in and around a residential development should be of paramount concern,
and the proposed advisory lanes on this section of Old Farm Road fails to provide a solution for
walkers.
• It is our understanding that Old Farm Road currently sees significant pedestrian traffic. Our
assumption is that increased volumes of drivers and walkers from the new development would only
increase what is already a significant safety concern and gap in our pedestrian infrastructure. The
alternative path directly east to Tilley Drive does not sufficiently address either of these issues along
this section of Old Farm Road.
4. Comprehensive Plan
The comprehensive plan includes a number of relevant statements related to transportation
system objectives.
• Objective 17. Provide a transportation network that complies with Complete Street
mandates and maximizes efficiency and safety for all types of users (pedestrians,
cyclists, transit, automobiles, trucks, rail, and air).
• Objective 20. Reduce the percentage of trips taken by single-occupancy vehicles in the
City.
• Objective 21. Seek alternative traffic congestion relief measures before existing
roadway segments are expanded.
5. Land Development Regulations
The following criterion of the Land Development Regulations have been discussed in previous
packets as relevant to this topic.
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15.18A(3) The project incorporates access, circulation and traffic management strategies
sufficient to prevent unreasonable congestion of adjacent roads. In making this finding the DRB
may rely on the findings of a traffic study submitted by the applicant, and the findings of any
technical review by City staff or consultants.
As noted above, a multimodal approach reduces the need for expanded vehicular roadways.
15.12M Sidewalks and Recreation Paths
(1) Unless otherwise provided in the specific regulations in Article 9 (SEQ) or in the City Center
Form Based Codes District, sidewalks and/or recreation paths shall be installed along both
sides of arterial streets, along both sides of collector streets in commercial areas, along one
side of collector streets in noncommercial areas, and along one side of local streets. The
specific location of sidewalks and/or recreation paths shall be determined by the DRB.
Acknowledging that this project is utilizing an existing roadway, it remains relevant that were
this a new project, the applicant would be required to construct a sidewalk or recreation path
along this collector roadway.
10.05 Transit Overlay District (TO)
A. Purpose. It is the purpose of the Transit Overlay District to provide for a safe, compact,
and efficient land use pattern that supports regular fixed-route transit service, pedestrian and
bicycle infrastructure. Certain land uses may be permitted only within the Transit Overlay
District, or be permitted outside the District subject to conditions. Other incentives or
requirements that complement a multi-modal environment may also be established.
The project is located in the Transit Overlay District. Residential use is allowed by right in the
transit overlay district.
6. Act 34 – Complete Streets Law
As described by the CCRPC, “in 2011, Governor Shumlin signed into law Act 34 which requires the
state and all municipalities to consider the needs of all users in all projects and all phases,
regardless of funding sources.” This act requires municipalities to include all users when
constructing new streets. In light of Act 34, Staff considers it appropriate to advocate for complete
streets when reviewing private projects.
Site Specific Factors Supporting Bicycle and Pedestrian Accommodations
• The Board and the applicant seem to agree with Staff that Old Farm Road should act as the central
feature of the proposed development.
• The development will create at least 135 additional homes, and opportunity for outdoor recreation
including trails and fields which are likely to draw those from adjoining neighborhoods. The increased
traffic on this road will decrease safety for the growing number of pedestrians without such a feature.
• The applicant testified that they do not want to provide a shared use path along the entire length of
Old Farm Road due to potential visual impacts to existing homes. The entire character of Old Farm
Road will be transformed as a result of this neighborhood, and the absence of complimentary
infrastructure along the southern portion will be more unexpected than the presence.
• A shared use path along the entire length will provide a benefit to the community when the
neighborhood is built out.
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• As noted by Staff at the field visit on 7/6, there is evidence of current use of Old Farm Road by
pedestrians.
• Encroachment of private landscaping into the public right of way is inadequate justification for
changing how the public way is used.
• The Board noted on April 20 that the project does not stand in a vacuum and off-site improvements
may be necessary to make the project compatible with it’s setting.
• It is the position of the City staff, City committees, and the independent technical review that a shared
use path along the entire length of Old Farm Road is an important element of the proposed project.
Staff has included two public comment letters which have not previously been provided to the Board in the
packet.
Recommendations of Staff
Staff recommends the Board require the applicant to provide a shared use path on the east side of Old Farm
Road. Staff acknowledges, however, the following possible options.
• Requirement that a bike/ped facility be designed and provided as part of final plat on east side of old
farm road, consisting of one of the following
o 10-ft wide asphalt shared use path – recommended alternative
o 8-ft wide asphalt shared use path
o 5-ft wide concrete sidewalk
• Payment in lieu - For project to provide payment for off-site bike/ped facilities for the City to use for
projects identified in Tilley Drive network study (see Figure 13 above), which include the applicant’s
proposed connection to Tilley Drive, facilities on Hinesburg Road, etc. This option would put it on the
City to determine which project best meets the needs of the City that has a nexus to the proposed
needs of the neighborhood. Ultimate allocation of funding would be determined by City Council.
• “Bicycle Advisory Lane” option presented by the applicant. Staff has reviewed the proposal for advisory
lanes with the Director of Public Works, and strongly disagrees with this approach. Old Farm Road is
not an appropriate location for such a treatment. Hinesburg Road, State Route 116, is a high to
medium speed roadway. Turning from such a roadway onto a road with shared bicycle and vehicular
lanes creates a potential safety concern.
With either the Old Farm Road or the Payment in Lieu option, Staff notes the Board may wish to consider
removing any requirement to construct the bike-ped connector from I/C Road to Tilley Drive.
Staff considers the Board should acknowledge the applicant’s strong opposition to constructing a multi-use path
south of the project area path because of a desire to not impact uninvolved adjoiners, but nonetheless
recommends the Board require the path be constructed. Staff is open to a phased approach or creative
solutions to construction of this section of the recreation path and recommends the Board to direct the
applicant to work with Staff prior to final plat. Further, Staff continues to be willing to meet with neighbors
between now and final plat to address site-specific design issues. Staff recommends the applicant be directed to
includes this recreation path in the final plat submittal.
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B) Traffic Study
The applicant has requested the Board make a determination on whether they will require the Kimball Ave
intersections to be constructed as roundabouts as part of this preliminary plat decision. The applicant
submitted a study entitled “Roundabout Feasibility Analysis,” prepared by Lamoureux & Dickinson Consulting
Engineers, Inc. dated June 21, 2021 in support of this request. The 17-page analysis provides a discussion of
traffic characteristics on Kimball Ave, a description of design considerations, a capacity analysis, a discussion of
the roundabout design process, and a preliminary cost estimate.
An independent third-party technical reviewer reviewed the analysis and provided a 1-page memo entitled
“Review of June 21, 2021 Roundabout Feasibility Analysis for Eastview – O’Brien Home Farm Application,”
prepared by BFJ Planning, dated July 12, 2021.
Staff recommends the Board review the 1-page memo from BFJ to inform their discussion of whether to
require the applicant to modify their design to include roundabouts in lieu of signalized intersections at the
intersections of Kimball Ave and Old Farm Road and Kimball Ave and I/C Road.
Recommendation
Staff recommends the Board conclude discussion of the above two topics and close the hearing.
Respectfully submitted,
Marla Keene, Development Review Planner
RaisedCrosswalk& RRFBOld Farm RoadAdvisory Bicycle LanesPotential Future ConnectionLEGENDPrepared: 4/1/21RecFieldParkParkCommunityCenterDog ParkKe
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Kimball AvenueTilley DriveAdvisoryBicycle LanesRaisedCrosswalk& RRFBNew SharedUse PathNew SharedUse PathNew SharedUse PathExisting Shared Use PathBike Connectivity to Be DeterminedDuring Phase 1 Plat PermittingProposed Shared Use PathProposed Advisory Bicycle LaneProposed CrossingChanges to Site PlanNew SharedUse PathGateway Feature(Transition from AdvisoryBike Lane to Shared Use Path)Future StreetConnection(By Others)New SharedUse Path
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Marla Keene
From:Brian Armstrong <barmstrong@kw.com>
Sent:Wednesday, May 26, 2021 11:16 AM
To:Marla Keene; Cathy Sarvis Iraheta; Douglas Dickey
Cc:Paul Conner; Douglas Dickey
Subject:EXTERNAL: Re: O'Brien Eastview information
This message has originated from an External Source. Please use proper judgment and caution when opening
attachments, clicking links, or responding to this email.
Marla and Paul,
Thank you again for time this morning and for the candor.
We appreciated the time you have both afforded us. I look forward to participating in the process from here on out. As
I ponder our discussion, the one bell that rings loudly with me is the fact that our neighbor was given a variance in the
subdivision for the Red Barn...as it's becoming a welcomed destination for many in the area... I wanted to put in writing
that intentionally or otherwise the variance the town gave is partially responsible for the very traffic they now want to
channel through my front yard.
With that said, I will go on record adamantly opposed to the request and suggest you revisit a southerly path over the
very parties property who was given the variance. I am prepared to be a vocal opponent to this and dedicate a
substantial amount of capital and court action to oppose it.
I respect our neighbor/s right to develop, yet the variance they requested resulted in traffic that should be channeled on
their land. Karmatically (some polite humor)... I believe that would be the most equitable. The lower tree line along their
property, an area which appears to have a proposed road along it likely would be a better fit and place the burden on
the party who benefited from the past variance.
With respect, care, and candor,
Brian Armstrong
Team Leader & Co-Founder at Keller Williams Vermont
Strong Will Real Estate & Property Management
o
:
e:
802.488.3494 m: 802.598.3190
barmstrong@kw.com w: allburlingtonhomes.com
a
:
68 Randall Street, South Burlington, VT 05403
"Live like you are going to die tomorrow, learn as if you are going to live forever." Gandhi
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representation, you are a customer and not a client. There is no confidentiality between us until there is a signed
brokerage service agreement. Link to disclosure: Click here for Disclosure
1
Marla Keene
From:Barbara Neff <babynurseneff@gmail.com>
Sent:Tuesday, July 6, 2021 10:06 AM
To:Marla Keene
Cc:Paul Conner
Subject:EXTERNAL: Site visit on July 6 at corner of Old Farm Road and Hinesburg Road
This message has originated from an External Source. Please use proper judgment and caution when opening
attachments, clicking links, or responding to this email.
Good morning, my name is Barbara Neff and I reside at 700 Hinesburg Road(on the corner of Old Farm Road). I have
spoken to Paul Conner recently and he alerted me to the meeting to take place on this date. I work full time at the UVM
Medical Center Hospital in the NICU and I will be working extra hours during your meeting time. As I will not be able to
voice my concerns or desires during your designated meeting time, I wish to send this email in hopes of being one of
the many voices of concern in your proposed future plans for a community walkway. I have had to contend with several
pedestrians along with occasional pets walking through the middle of my yard to gain access to the market or sidewalk
next door. A path has been mowed through the run‐off area adjacent to our yard and people have been going through
our yard almost daily. I wish to object to a proposed future permanent walkway bisecting our yard to gain access to the
market next door. If a proposed walkway is inevitable then it should be connected to the already existing walkway on
the west side of Hinesburg Road with appropriate cross‐walk options in place. Since there will be a future traffic light
placed at the Tilley Drive site, the traffic pattern will slow/stop at the Old Farm Road corner to allow for a cross‐walk
option to be placed there. Possibly moving the entrance to Old Farm Road further to the south of where it is now may
prevent the rather “fast” exits to the road and slow the turning vehicles . I see several alternate options and possibilities
to gain a safe and pleasant walkway for the increasing pedestrian traffic in our very near future. I would like it to be
known, that I, Barbara Neff of 700 Hinesburg Road, do Not wish that walkway to be placed in the middle of our family
yard. As a side note…. I am a Tilley member and my children are the 5th generation to grow up in this farmhouse. We
have seen countless changes occur at this site in the last 17 years and I am encouraging a change of future plans for the
walkway out of respect for what remains of our home site. Very sincerely yours, Barbara Neff
Lamoureux & Dickinson
Consulting Engineers, Inc.
TECHNICAL MEMORANDUM
Project: O’Brien Home Farm - Eastview
Date: June 21, 2021
From: Roger Dickinson, PE, PTOE
Subject: Roundabout Feasibility Analysis
As requested, outlined below are the results of our examination of constructing roundabouts instead of
traffic signals on Kimball Avenue at the relocated Old Farm Rd and new I/C Road intersections.
Eastview’s Proposed Kimball Ave Improvements
The Eastview development currently proposes two new intersections on Kimball Avenue. The first is the
relocated Old Farm Rd intersection which will form a four-way intersection with the existing driveway to
the 20-30 Kimball Ave office complex. The second will be the new I/C Road intersection which will also
form a four-way intersection with the INS office building’s existing driveway at 70 Kimball Ave.
Both intersections will operate initially under two-way stop-control. New exclusive left-turn lanes are
proposed on Kimball Ave at both intersections in order to provide additional capacity and to maintain
safe traffic flow. With Kimball Ave being 32 ft wide curb-to-curb, and with Eastview also constructing a
new shared-use path along its south side, those left-turn lanes can be pavement-marked using a 11’-10’
11’ cross-section; thus, not requiring any roadway widening. It is recommended that the Kimball Ave
left-turn lanes be installed at the same time each intersection is initially constructed. Eastview’s revised
traffic impact assessment1 also recommended providing an exclusive right-turn lane on the I/C Road
approach once the Tilley Drive connection is made in order to provide additional capacity for that
movement exiting onto Kimball Ave.
As Eastview is developed and the I/C Road extended to link with Tilley Drive, it is anticipated future
traffic volumes will warrant the installation of traffic signals at both intersections. These signals will be
triggered by the proposed development as outlined in the Traffic Impact Analysis submitted and in the
record for this hearing at Exhibit 014. Importantly, it is not anticipated that the future traffic signals will
require any widening of Kimball Ave or further geometric improvements other than those outlined
above.
Kimball Ave Traffic Characteristics
In order to examine the pros and cons of roundabouts vs. traffic signals, it is important to understand
existing traffic characteristics. Kimball Ave is an urban major collector roadway linking Kennedy Dr with
the Taft Corners/I-89 Exit 12 area in Williston. Kimball Ave, together with Marshall Avenue in Williston,
also provides access to numerous commercial and industrial properties in both municipalities.
1 Eastview - O’Brien Home Farm Traffic Impact Assessment, Lamoureux & Dickinson, March 30, 2021
Lamoureux & Dickinson Page 2
Consulting Engineers, Inc.
The Vermont Agency of Transportation (VTrans) most recently performed an automatic traffic recorder
count on Kimball Ave just east of Old Farm Rd in early August 2019. The observed average weekday
volume in that count was 12,562 vehicles per day (vpd). Figure 1 illustrates the observed weekday
hourly volumes.
Figure 1 - Kimball Avenue Weekday Traffic Volumes
That count also classified the types of vehicles traveling Kimball Ave. The data showed that single-unit
trucks/buses make up 7% and that semi-trailer trucks make up 1% of weekday traffic. Those
percentages are considerably higher than the statewide average truck percentages on urban major
collectors (4.4% single-unit trucks/buses and 0.5% semi-trailer trucks). Table 1 presents the numbers of
trucks traveling Kimball Ave on a typical weekday (based on 12,562 vpd).
It is important to note that the above are pre-development volumes. These numbers also do not include
the additional truck trips associated with the FedEx facility newly built on Community Drive which will
increase truck traffic on Kimball Avenue.
Table 1 - Kimball Ave Weekday Truck Volumes
Truck Type
FHWA
Vehicle Class
Volume
(vpd)
Single-Rear Axle Straight Trucks & Buses 4 - 5 667
Tandem & Tri-Rear Axle Straight Trucks 6 - 7 147
Short Semi-Trailers (4 axles, WB-40 & WB-50) 8 68
Long Semi-Trailers (5 axles, WB-62 & WB-67) 9 - 10 47
Double Trailers 11 - 13 1
Total 930
It should also be noted that during the permitting process for the FedEx facility, the Development
Review Board examined a similar proposal for a roundabout or a traffic signal at the Kimball Ave/
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Lamoureux & Dickinson Page 3
Consulting Engineers, Inc.
Gregory Dr/Community Dr intersection (exactly what is being discussed here), with similar traffic
conditions. The Board eventually found that: “the revised signal design meets City objectives.”2
Roundabout Design Elements
There are six basic roundabout categories used in designing roundabouts, depending on the character of
the area and the highways served.3 Both Georges Jacquemart, PE, the City’s consultant, and this writer
agree that only single-lane roundabouts should be considered on Kimball Ave; thus, eliminating the two
double-lane categories.4 The primary reasons for not considering double-lane roundabouts are their
larger size, increased complexity for motorists plus increased difficulty for pedestrians. Figure 2
illustrates the basic design elements of a roundabout. Table 2 lists the single-lane roundabout
categories together with their key design elements.5
Figure 2 - Typical Roundabout
Table 2 - Typical Roundabout Design Elements
2 See page 4 of the Preliminary Plat and Final Plat Application SD-19-22 of SunCap Property Group,
recorded at Vol 1495. Page 252 of the City of South Burlington Land Records.
3 Roundabouts: An Informational Guide, Federal Highway Administration, June 2000, Exhibit 1-6
4 The sixth category is a rural single-lane roundabout.
5 Roundabouts: An Informational Guide, Exhibit 1-7
Lamoureux & Dickinson Page 4
Consulting Engineers, Inc.
Design Element Mini-Roundabout Urban Compact Urban Single-Lane
Recommended Entry Speed 15 mph 15 mph 20 mph
Maximum Number of Entering
Lanes per Approach 1 1 1
Typical Inscribed Diameter* 45-80 ft 80-100 ft 100-130 ft
Splitter Island Treatment Raised,
if possible
Raised, with
crosswalk cut
Raised, with
crosswalk cut
Typical Daily Service Volumes* 10,000 vpd 15,000 vpd 20,000 vpd
* Assumes 90° entries and no more than four-legs.
Accepted roundabout design practice is to use a 110 ft inscribed diameter as the minimum needed to
adequately accommodate WB-62 and WB-676 semi-trailer trucks. Smaller diameter roundabouts are
certainly possible, but their central island will need to be designed to be driven over by semi-trailer
trucks. As can be seen in Table 2, mini-roundabouts and urban compact roundabouts provide less
capacity than urban single-lane roundabouts.
In Vermont, comparable examples of heavily traveled urban roundabouts include the intersection of
Main St and Cross St in Middlebury and the intersection of VT Routes 7A and 11 in Manchester. Both
have an inscribed circle diameter of ±110 ft. The Glens Falls roundabout, which has been cited by
Georges Jacquemart, PE, as an example of an urban roundabout, has an inscribed circle diameter of 115
ft.
Alignment is another critical roundabout design element. Figure 3 illustrates the three alignment
options; offset left, radial and offset right. A roundabout’s alignment is a major factor in how well it will
reduce the speed of entering vehicles to the recommended entry speed. In other words, the desired
deflection, and corresponding speed reduction, of traffic entering a roundabout is easier to achieve with
the offset left alignment.
6 A semi-trailer truck having a 53 ft long trailer is commonly referred to as a WB-67 design vehicle.
However, Vermont and other eastern states require that the kingpin distance on 53 ft trailers not exceed
41 ft; effectively changing that vehicle to a WB-62 design vehicle for purposes of analyzing turning paths.
Lamoureux & Dickinson Page 5
Consulting Engineers, Inc.
Figure 3 - Roundabout Alignment Options
The above roundabout design elements are presented to help readers of this Technical Memorandum
understand the background of how these design elements influence the pros and cons of installing
roundabouts on Kimball Ave. This memorandum will reference these design elements in the following
sections.
Roundabout Design Selection
Given the above, this memorandum provides analysis of the impacts and feasibility for installing an
Urban Single Lane Roundabout, with a 110’ inscribed circle diameter. This design was selected for two
main reasons:
Capacity: Given the current traffic volumes on Kimball Avenue and the potential of significant
additional development in the area, choosing a design that would exceed the recommended daily
volume of 10,000 vpd (Mini-Roundabout) or only allow for a relatively small increase to 15,000 vpd
(Urban Compact Roundabout) does not seem prudent.
Truck Turning Movements: It is well known that Kimball Avenue is a heavily traveled truck route.
This is documented in the numbers provided above. Given this, providing a roundabout on a high-
volume major collector street which would necessitate trucks to drive over its central island does not
represent good design. There are inherent safety concerns associated with that, not to mention the
disruptions in traffic flow caused by those vehicles.
The following sections review the impacts of an Urban Single-Lane Roundabout and the levels of service
provided.
Lamoureux & Dickinson Page 6
Consulting Engineers, Inc.
Intersection Capacity
For roundabouts, the maximum volume of conflicting traffic at its entry points is a critical capacity
limitation. The conflicting traffic volume equals the sum of entering traffic and circulating volume at
each entry point. Research has shown that the capacity of a single-lane roundabout max’s out at a
conflicting volume of 1,300 - 1,600 vehicles per hour (vph) at its entry points.7 A good rule of thumb for
design purposes is to limit the conflicting volume to 1,100 vph for satisfactory operation during peak
periods.8
Table 3 presents the critical conflicting volumes associated with the projected 2032 Eastview Full-Build
traffic analysis scenarios.
Table 3 - Projected Maximum Conflicting Volumes
Peak
Hour Critical Entry Point
Max. Conflicting Volume (vph)
Old Farm Rd I/C Road
AM
Kimball Ave Eastbound
without future connectors
with future connectors
1,245
1,117
1,280
1,231
PM
Kimball Ave Westbound
without future connectors
with future connectors
1,619
1,574
1,574
1,502
As outlined above both the AM and PM peak hours will see vehicle volumes in excess of the 1,100 vph
design threshold recommended by the New York State Department of Transportation Roundabout
Design Unit.
That future peak hour traffic volumes on Kimball Ave exceed what a single-lane roundabout is capable
of handling is reinforced by the results of capacity analyses performed using roundabout capacity
analysis methodology from the Highway Capacity Manual. Those results are shown in Table 4 together
with the results for signalized intersections.
Table 4 - Intersection Levels of Service
Peak
Hour Critical Entry Point
Roundabouts Signalized
Old Farm Rd I/C Road Old Farm Rd I/C Road
AM
Kimball Ave Eastbound
without future connectors
with future connectors
D
C
E
D
C
C
C
B
PM
Kimball Ave Westbound
without future connectors
with future connectors
F
F
F
F
C
C
D
C
7 Highway Capacity Manual, Transportation Research Board, 6th Edition
8 Modern Roundabout Design, New York State Department of Transportation Roundabout Design Unit
Lamoureux & Dickinson Page 7
Consulting Engineers, Inc.
As outlined above, the Project is currently proposing signalized intersections which maintain a level of
service of D or better for all hours, and which in large part are at a C or better. Importantly, these levels
of service are maintained even without the future connections and roadway networks that are outside
the control of Applicant. It is of paramount importance to the Applicant that the investment in traffic
improvements enable their project to proceed. As outlined above, a single-lane roundabout does not
provide sufficient capacity to maintain desired levels of service on Kimball Avenue.
Intersection Alignment
As noted above, the proposed signalized intersections at the relocated Old Farm Rd and the new I/C
Road will not require extensive roadway widening or realignment. Kimball Ave is already sufficiently
wide to create the desired left-turn lanes at both intersections by restriping the existing pavement
markings. At most, a thin mill and overlay of the existing pavement would eliminate any remnants of
the old pavement markings and help the new pavement markings stand out visually.
The close proximity of on-site parking and internal driveways at the #20-30 Kimball Ave office complex
complicates installing a roundabout serving that office complex and the relocated Old Farm Rd. A
radially aligned roundabout having a 110’ inscribed circle diameter is shown in Figure 4. The inscribed
circle diameter is shown by the orange circle. The yellow dashed line with a band of hatching on the
inside delineates the perimeter of the area needed for the roundabout together with green strips, a
sidewalk (north side) and a shared-use path (south side).
The radial roundabout shown in Figure 4 is incompatible with the existing internal driveways and
parking at the #20-30 Kimball Ave office complex. It would also require acquiring land and/or
easements to construct; potentially involving as many as four parcels which have rights to use the
existing access onto Kimball Ave. For these reasons, an offset roundabout at this intersection was also
examined, and is shown in Figure 5.
With the roundabout shown in Figure 5 potentially creating an unacceptable offset right alignment
under the design guidelines outlined above, realigning both Kimball Ave approaches to restore a radial
alignment will be required. This will involve constructing new approaches on Kimball Ave for 200-250’
on each side of the roundabout.
The construction of a roundabout at the relocated Old Farm Road intersection will therefore require the
reconstruction of approximately 400-500’ of Kimball Avenue, in addition to the construction of the
roundabout itself and associated improvements.
Figure 6 illustrates a radial roundabout at the new intersection where the I/C Road will intersect with
Kimball Ave directly opposite the existing driveway accessing #70 Kimball Ave (the INS Building). It is
notable that this roundabout can be placed without causing significant issues with the existing access at
70 Kimball Avenue, however this placement will again require additional land and/or easements from
the #70 Kimball Ave parcel. An offset roundabout would help avoid the need for those easements, but
would add the need to relocate and rebuild a portion of Kimball Avenue similar to what is described
above at Old Farm Rd.
Lamoureux & Dickinson Page 8
Consulting Engineers, Inc.
Figure 4 - Radial 110’ Ø Roundabout at Relocated Old Farm Rd
Figure 5 - Offset 110’ Ø Roundabout at Relocated Old Farm Rd
Lamoureux & Dickinson
Consulting Engineers, Inc.
Figure 6 - Radial 110’ Ø Roundabout at I/C Road
Intersection & Approach Grades
Kimball Ave is located on a relatively flat vertical alignment. To the north, the surrounding land is also
predominantly flat or gently sloping away from Kimball Ave. To the south, however, is a significant
hillside, the top of which on Old Farm Rd is approximately 80 ft higher than Kimball Ave.
Conventional intersections, whether signalized or not, are fairly tolerant of moderate grades. Obviously,
as roadway grades increase, acceleration and deceleration distances increase, and issues with safe
vehicle operation emerge. Roadways having an uphill grade as they approach a conventional
intersection will also experience reduced capacity.
Roundabouts operate better when constructed on a relatively flat grade. Recommended design practice
is to design roundabouts so that the central island is the high point, with drainage being directed to the
outside of the roundabout.
Both the relocated Old Farm Rd and the new I/C Road will slope down to Kimball Ave at a steep grade.
The civil site engineer, Scott Homsted, PE, of Krebs & Lansing Consulting Engineers, Inc. has examined
the additional grading and earthwork that will be required by roundabouts at these two proposed
intersections. His analysis is enclosed in Appendix A.
Lamoureux & Dickinson Page 10
Consulting Engineers, Inc.
Potential Construction Costs
The construction costs for installing traffic signals are well documented, and typically can be estimated
at about $250,000 per intersection. The installation of left-turn lanes in Kimball Ave will add another
$50,000 - $100,000 to that (per intersection), depending on whether any widening or pavement
overlays are required. As outlined above, no pavement widening is proposed in this Project and
therefore it is expected that the full cost of each new intersection could be as much as $350,000.
In comparison, the proposed roundabouts at both the I/C Road and Relocated Old Farm Road have
estimated construction costs that are likely to be substantially higher. Estimating these costs would
require detailed project plans that would address: traffic control and detouring, work hours (night or day
work), utility relocation, roadway relocation, stormwater management and location, site grading,
pedestrian infrastructure and locations/type and materials, landscaping, lighting, striping and signage, in
addition to all relevant roadway planning standards. The development of these plans in and of itself is
something that would be a substantial cost in and of itself.
Table 5 outlines the size (inscribed circle diameter) and cost of several roundabout projects where we
have been able to ascertain cost from local news sources, including the Glens Falls example.
Table 5 - Roundabout Cost Examples
Location Diameter Total Project Cost
Waterbury, VT (US 2/VT 100) 140' $5,000,000
Burlington, VT (Shelburne St Rotary) $7,777,000
Glens Falls, NY (Centennial Circle) 115' $9,000,000
Hartford, VT (US 5 & Sykes Ave) (2 roundabouts) 105' / 140' $6,829,000
The above roundabout costs are significantly greater than the cost of traffic signals. While adjustments
for size and complexity can certainly be made, the average cost for the examples cited above exceeds
$5MM per location. At 20% of that, the cost would still be over $1MM and more than three times the
cost of the traffic signal alternative.
In terms of impacts (cost and convenience), it should also be considered that the roundabouts being
discussed would require major construction on Kimball Avenue; resulting in lane closures and/or the
construction of detours to facilitate construction. The construction will likely cause a ripple effect on
nearby roadways and disrupt traffic in over a large area in both South Burlington and Williston.
Conclusions
In summary, the above examines major considerations associated with whether to use conventional
intersections or roundabouts at Eastview’s two proposed intersections on Kimball Ave. As outlined
above, single-lane urban roundabouts have been examined as an alternative to traffic signals. The
results of this examination show that single-lane roundabouts would result in significantly greater traffic
congestion. In addition, their greater construction cost (and traffic disruption during construction)
Lamoureux & Dickinson Page 11
Consulting Engineers, Inc.
cannot be justified. For all of these reasons, the Project has proposed signalization as the preferred
method of traffic control at these two new intersections.
Lamoureux & Dickinson
Consulting Engineers, Inc.
APPENDIX A
Eastview Roundabout Grading Impacts
Memo
164 Main Street, Suite 201 | Colchester, Vermont | P: (802) 878-0375 | email@krebsandlansing.com
Date: June 10, 2021
To: Andrew Gill
From: Scott Homsted
Re: Eastview Roundabout Grading Impacts
We analyzed the grading impacts of installing roundabouts instead of traffic signals on Kimball Avenue at the
relocated Old Farm Road and I/C Road intersections. We identified the following:
Relocated Old Farm Road
We looked at impacts to the relocated Old Farm Road and adjacent lots using an offset roundabout with a 110’
inscribed circle diameter. The offset roundabout was used to avoid untenable impacts to the #20-30 Kimball Ave
office complex.
The O’Brien land in the area of the intersection adjacent to Kimball Avenue is a steep slope with grades up to
20%. Because the roundabout will be offset, the center island of the roundabout will need to be located on
what is now a steep slope. Grades within the area of the roundabout will be limited to 2% to meet ADA
requirements. Therefore, very significant cuts and earth moving, likely including blasting of ledge, will be needed
to install the roundabout.
The grading impacts from a roundabout extend up the relocated Old Farm Road. The grade for Old Farm Road is
required to be no more than 3% within 100’ of the intersection. This section of road is going to be in a cut
section regardless of the type of intersection. However, due to the roundabout shifting the intersection south
onto the property, the cut section becomes much deeper. A signalized intersection results in the finish grade of
the new road being up to 6’ below existing ground. The roundabout intersection results in the finish grade being
up to 10’ below existing ground. Importantly, the deeper cut required impacts the road all the way to the
O'Brien Farm Road intersection. The current intersection grade at O'Brien Farm Road would not be able to be
met without using 250'-300' feet of 10% grade along Old Farm Road, which is not desirable, or even allowed
under the current South Burlington road standards.
Lots 23 and 26 will also be greatly impacted by a potential roundabout. Because the roundabout radii extend
onto these lots, the grading impacts will extend as well, pushing the cut section onto the lots. While buildings on
these lots will likely be above the road regardless of intersection type, the extra cut for the road will cause the
buildings to be even higher above the road grades. This will affect the aesthetics of the development and make
it difficult to achieve the “gateway” effect that both the developer and City are looking for.
I/C Road
We looked at impacts to the proposed I/C Road and adjacent lots using a radial roundabout with a 110’ inscribed
circle diameter.
Andrew Gill
Roundabout Grading Memo
June 10, 2021
PAGE [ 2 ]
The O’Brien land in the area of the I/C intersection adjacent to Kimball Avenue is a moderate to steep slope with
grades up to 12%. Grades within the area of the roundabout will be limited to 2% to meet ADA requirements.
The size of the roundabout pushes the intersection onto project property, causing the new road to start off in
more of cut section than a signalized intersection. The grade for the I/C road is also required to be no more than
3% within 100’ of the intersection. Similar to Old Farm Road, the I/C Road is going to be in a cut section
regardless of the type of intersection. However, due to the roundabout shifting the intersection south onto the
property, the cut section becomes much deeper. A signalized intersection results in the finish grade of the new
road being 6-8’ below existing ground. The roundabout intersection results in the finish grade being over 10’
below existing ground in places.
Submitted by,
Scott Homsted, P.E. #7893
INTERSECTION
WITH O'BRIEN
FARM ROAD
Finish Grade centerline
using SIGNALIZED
intersection
EXISTING
KIMBALL
AVENUE EDGE
OF PAVEMENT
3%
8%
9.
4%
3%
1
0%
2%
3%
OFFSET
ROUNDABOUT
WITH MAXIMUM
SLOPE OF 2%
3% SLOPE
MAXIMUM GRADE
WITHIN 100' OF
INTERSECTION
10% GRADE NEEDED
FOR 260 FEET TO
MATCH GRADE AT
O'BRIEN FARM ROAD
INTERSECTION
Finish Grade centerline
using ROUNDABOUT
intersection
Approximately 6' cut required
from existing ground to
finished paved surface using
SIGNALIZED intersection
Approximately 10' cut
required from existing ground
to finished paved surface
using SIGNALIZED
intersection
HILLSIDE @
O'BRIEN FARM
OWNER AND APPLICANT:
ISSUED FOR PERMIT REVIEW
NOT FOR CONSTRUCTION
PROPERTY INFORMATION:
CP-4A
Old Farm Road and Kennedy Drive,
South Burlington, Vermont
O'BRIEN BROTHERS
1855 WILLISTON ROAD
SOUTH BURLINGTON, VT 05403
164 Main Street, Suite 201 P: (802) 878-0375
Colchester, Vermont 05446
email@krebsandlansing.com
ROAD PROFILE
RELOCATED
OLD FARM ROAD with
ROUNDABOUT OVERLAY
EASTVIEW
Finish Grade
centerline using
SIGNALIZED
intersection
EXISTING
KIMBALL
AVENUE EDGE
OF PAVEMENT
ROUNDABOUT
WITH MAXIMUM
SLOPE OF 2%
3% SLOPE
MAXIMUM GRADE
WITHIN 100' OF
INTERSECTION
8% MAXIMUM GRADE
FOR ROAD DESIGNED
AS "COLLECTOR"
STREET
Finish Grade centerline
using ROUNDABOUT
intersection
Approximately 7' cut required
from existing ground to
finished paved surface using
SIGNALIZED intersection
Approximately 12' cut
required from existing
ground to finished paved
surface using SIGNALIZED
intersection
8%
2%
3%
HILLSIDE @
O'BRIEN FARM
OWNER AND APPLICANT:
ISSUED FOR PERMIT REVIEW
NOT FOR CONSTRUCTION
PROPERTY INFORMATION:
CP-11A
Old Farm Road and Kennedy Drive,
South Burlington, Vermont
O'BRIEN BROTHERS
1855 WILLISTON ROAD
SOUTH BURLINGTON, VT 05403
164 Main Street, Suite 201 P: (802) 878-0375
Colchester, Vermont 05446
email@krebsandlansing.com
ROAD & UTILITY
PROFILE
I/C ROAD with
ROUNDABOUT OVERLAY
EASTVIEW
RELOCATED OLD FARM ROAD
WITH SIGNALIZED
INTERSECTION
RELOCATED OLD FARM ROAD
WITH ROUNDABOUT
INTERSECTION
I/C ROAD WITH SIGNALIZED
INTERSECTION
I/C ROAD WITH ROUNDABOUT
INTERSECTION
HILLSIDE @
O'BRIEN FARM
OWNER AND APPLICANT:
ISSUED FOR PERMIT REVIEW
NOT FOR CONSTRUCTION
PROPERTY INFORMATION:
CX-1A
Old Farm Road and Kennedy Drive,
South Burlington, Vermont
O'BRIEN BROTHERS
1855 WILLISTON ROAD
SOUTH BURLINGTON, VT 05403
164 Main Street, Suite 201 P: (802) 878-0375
Colchester, Vermont 05446
email@krebsandlansing.com
ROUNDABOUT
CROSS SECTIONS
EASTVIEW
MEMORANDUM
BUCKHURST FISH & JACQUEMART, INC. 115 FIFTH AVENUE NEW YORK, NY 10003 T. 212.353.7474 F. 212.353.7494
Date: July 12, 2021
To: Marla Keene, PE, Development Review Planner
Paul Conner, AICP, MCIP, Director of Planning & Zoning
From: Georges Jacquemart
Contact Information: T. 212.353.7477 F. 212.353.7494 E. G.Jacquemart@bfjplanning.com
Subject: Review of June 21, 2021 Roundabout Feasibility Analysis for Eastview – O’Brien
Home Farm Application
The purpose of this memorandum is to summarize our review of the June 21, 2021 Memorandum prepared by
Lamoureux & Dickinson Consulting Engineers, Inc (LDC) in regards to the roundabout feasibility to mitigate impacts of the second phase of the O’Brien Home Farm mixed-use development. In our previous review of the
preliminary evaluation we requested a level of service analysis of a single-lane roundabout at the two
intersections along Kimball Avenue. The June 21, 2021 Memo by LDC includes this operational analysis, as well
as other evaluation criteria. We do accept the level of service F projection for the PM peak hours in Table 4 of
the Memo as the key conclusion that single lane roundabouts are not feasible at these locations, however, we would like to obtain a clarification of the source of that calculation. The LDC memo mentions the Highway
Capacity Manual, 6th Edition. Is that the 2010 HCM or the 2000 HCM? Could the applicant submit the print-out of these calculations?
We have also the following secondary comments for general information (we do not expect any responses to
these comments):
The discussion of the high percentages of truck in the traffic stream should not be a criteria in favor of signalized
intersections, since roundabouts can be designed for larger vehicles and we have good examples of roundabouts carrying high percentages of trucks in the US and in Vermont (Brattleboro). In fact, given that the
truck percentages are generally highest in the off-peak hours, roundabouts have the advantage of significantly
reducing idling, pollutant emissions and fuel consumption during off-peak hours, and if diesel trucks are an
important component of those traffic streams the sustainability benefits of roundabouts become significant.
In regards to cost comparisons between the two options it is important to not only mention construction costs,
but also operational costs, i.e. annual maintenance costs and costs of crashes, especially when one of these
costs may be borne by the applicant, and the others are borne by the community. Resiliency in view of severe weather events should also be an evaluation factor.
We do not fully agree with all the design criteria between signalized intersections and roundabouts such as the
2% approach limit for roundabouts and 3% for signalized intersections. It should also be noted that some of the
planning and design criteria mentioned in the LDC memo referring to the Year 2000 FHWA Roundabout
Informational Guide have been superseded by the 2010 Second Edition Guide (NCHRP Report 672). Typical
daily service volumes have increased significantly for the various types of roundabouts.
Please let us know if you have any questions.