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Alternatives
Evaluation

Having evaluated the existing conditions and having worked closely with city staff
and city officials (May 2, 2013 Joint meeting of Board of Aldermen Committee on
Infrastructure and Planning & Economic Development Committee) on defining
study area problems, issues and constraints, and potential solutions, a range of
alternatives were developed. Based on this initial input, the developed alternatives
focused on opportunities to convert some of the many one-way streets to two-way
flow. In addition, alternatives were developed that considered opportunities to
reconfigure the Walnut Street Oval in an effort to both improve mobility and to
encourage economic development. Once the initial alternatives evaluation was
completed, the alternatives were presented to the public at a public workshop for
additional input and consideration.

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3.1. Conceptual Alternatives

The following sections describe the various alternatives that were brought to the
April 30, 2014 public workshop. The alternatives include various configurations for
the Walnut Street Oval, pedestrian enhancements for the Water Street area,
considerations for converting several Downtown streets from one-way to two-way
operation, and consideration of introducing concurrent pedestrian phasing at all
Downtown traffic signals.

B 3.1.1 Walnut Street Oval

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Reconfiguring the Walnut Street Oval would not only afford the City an opportunity
to enhance access to the Downtown from the west (complimenting the Broad Street
Parkway), but it would also provide a tremendous opportunity to both encourage
redevelopment and introduce a more pedestrian friendly appeal to the area. A range
of reconfiguration alternatives were considered. Alternatives included reconfiguring
the Walnut Street Oval into a grid pattern, reconfiguring into a more conventional

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signal or roundabout in the southern or northern portion of the oval, and
reconfiguring the Oval using two roundabouts.

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Figure 13: Walnut Street Oval Grid Pattern Circulation Alternative

Reconfiguring the Oval into a grid pattern would closely follow the existing roadway
layout as shown in Figure 13 while maintaining the building located in the center of
the Oval. This would increase circulation between the western portions of the study
area with Main Street particularly if combined with traffic flow modifications along
West Pearl Street and Factory Street. This alternative would provide an important
connection from the Broad Street Parkway entering the Mill Yard along Central
Street, onto West Pearl Street and onto Main Street. However each intersection
within the grid would require traffic control modifications. A combination of stop
sign controlled and/or traffic signal controlled intersections may be required
depending on the modified traffic volume patterns.

Reconfiguring the Walnut Street Oval into a single consolidated intersection at the
southerly end of the existing Oval (near West Pearl Street) could be controlled by
either a traffic signal or a roundabout. The traffic signal and roundabout
configurations are depicted in Figure 14.

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ROUNDABOUT CONCEPT

Figure 14: Walnut Street Oval Southern Consolidation Alternatives

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Similarly, alternatives were developed and considered that create a single
consolidated intersection at the northerly end of the existing Oval. Like the southerly
options, this intersection could also be placed under traffic signal control or be
constructed as a roundabout. The Northern Alternatives are shown in Figure 15.
Note that one downside to the single consolidated intersection is that it limits direct
access to side streets such as High Street and School Street. The consolidated
northern intersection also limits the amount of available developable land.

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* SIGNALIZED CONCEPT ROUNDABOUT CONCEPT |
Figure 15: Walnut Street Oval Northern Consolidation Alternatives

Because the single consolidated intersection (both the northern concept and the
southern concept) limit redevelopment opportunities, an additional set of
configurations were developed. As shown in Figure 16, these concepts involve the
construction of two roundabouts — one to the south near West Pearl Street and one to
the north near High Street. The advantage of these configurations is that they leave
substantial developable land that can serve to encourage redevelopment and
economic opportunities.

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Figure 16: Walnut Street Oval Dual Roundabout Alternatives
The Chestnut Street Separation concept provides two 3-legged roundabouts, one in
the north and one in the south. The northern roundabout combines High Street,
Factory Street and Walnut Street while the southern roundabout combines Walnut
Street Central Street and West Pearl Street. There is a T-intersection of Clocktower
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Place with Walnut Street and a second T-intersection of Chestnut Street with Central
Street. Of the concepts with two roundabouts, the Chestnut Street Separation
concept results in the least amount of property impact with only the central oval
property being encroached upon. However the T-intersection of Central Street and
Chestnut Street is located in close proximity to the approach to the southern
roundabout. Under current traffic flow patterns, Chestnut Street has a high
southbound volume. These left-turns would be in conflict with the Central Street
traffic. This would be an area of concern for an increase in conflicts, delay and
confusion to drivers.

To address this issue, the Chestnut Street Integration Concept was developed. This
eliminated the conflict for the Chestnut Street traffic by combining Chestnut Street
into the southern roundabout in a 4-leg design. This concept results in property
impacts to multiple properties.

Table 4 — Clocktower & Chestnut St Integration Concept Roundabout Analysis Summary

North Roundabout South Roundabout

AM Peak Hour PM Peak Hour AM Peak Hour PM Peak Hour

Delay** LOS*** Delay LOS Delay LOS Delay LOS

NB 5 A 7 A N/A N/A N/A N/A
WB 6 A 7 A 10 B 13 B
SB 5 A 6 A 8 A 12 B
EB 8 A 8 A 10 A 13 B
Overall 7 A 7 A 9 A 12 B

** Delay in seconds per vehicle,

*** Level of Service

A final dual roundabout alternative was considered that consolidates the roadways
into two 4-legged roundabouts. This concept would connect Clocktower Place
directly into the northern roundabout. Additional properties are impacted with the
configuration. Table 4 shows the summary of the analysis results of the Clocktower
& Chestnut St Integration Concept. With this alternative the roundabouts will
operate at LOS B or better without having nearby intersections that would creating
confusion and increasing overall delay.

Although each option has its advantages and disadvantages, the duel roundabout
option would appear to provide the best opportunity to enhance vehicular and
pedestrian mobility while encouraging area redevelopment. The dual roundabout
alternative, specifically the Clocktower & Chestnut St Consolidation Concept
therefore will be the alternative included for screening and evaluation purposes.

B 3.1.2 Water Street

If one or more private developers, in collaboration with the City, were to advance a
pedestrian friendly redevelopment plan for the Walnut Street Oval area, it would be
advantageous to provide continuous pedestrian connectivity to the Nashua River at

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Water Street. This could be done by converting the western segment of Water Street
to a pedestrian corridor/park. This conversion to a pedestrian corridor could be
relatively straight forward as the existing western segment of Water Street could be
closed to vehicular traffic and converted. Figure 17 shows a concept of what Water
Street could look like as a pedestrian corridor.

Figure 17: Water Street Pedestrian Corridor

Full vehicular access and egress would be maintained for all businesses on Water
Street by way of the traffic signal controlled Main Street intersection. Traffic
operations at the Water Street /Park Street /Main Street intersection would be
expected to show a modest improvement due to the reduced traffic volume on the
Water Street approach. Vehicles that currently use Water Street and are not destined
to one of the local businesses on Water Street would divert to other existing
roadways, primarily Factory Street.

While this would reduce some vehicular circulation throughout the downtown, it
would increase pedestrian and bicycle use. The pedestrian corridor, which would
connect to Factory Street, would not only provide access to pedestrians and
bicyclists, but it would provide an aesthetically pleasing area with landscaping,
benches, and great views of the River.

B 3.1.3 Factory Street

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The portion of Factory Street from Water Street to Main Street and Temple Street
from Spring Street to East Pearl Street would be transitioned from existing one-way
eastbound (except the section of Temple Street from Main Street to Spring Street that
presently services two-way traffic flows) to two-way traffic flow under the Factory
and/or Temple Street two-way conversion alternative. This alternative is illustrated
in Figure 18.

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Figure 18: Factory Street and/or Temple Street Two-way Conversion Alternative

Table 5 - Signalized Inter:

Main St. at Water/Park St.

Main St. at Factory/Temple St.

Converting Factory Street to two-way operation while maintaining full access/egress
at Water Street would be problematic given the poor sight line available for motorists
turning from Water Street. The sight line is limited by the building located on the
northeast corner of the Factory Street/Water Street intersection. However, the sight
line issue would be negated if the Factory Street two-way conversion was combined
with the closure of the west segment of Water Street as provide under the Water
Street Pedestrian Corridor alternative.

section Capacity Analysis Summary
2-Way Alternative

Existing 1-Way (2-Lane West Approach

(Excl. PED) Split Phase and Excl. PED)

v/c* Delay** LOS*** v/c Delay LOS
PM 0.62 29 t 0.63 26 Cc
PM 0.46 26 C 0.71 36 D

* Volume to Capacity Ratio.
** Delay in seconds per vehicle,

*** Level of Service.

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Under this two-way conversion, the intersection of Main Street at Factory

Street /Temple Street show an increase in delay and drop a level of service from LOS
C to LOS D during the weekday evening peak hour. This deterioration in operations
is due to the need to add phases to the existing traffic signal. The rule of thumb is
when a phase is added to an existing traffic signal, operations will decrease one level
of service. This is what occurs here. There is potential to mitigate some of this
increase in delay if the exclusive pedestrian phase was removed and current
pedestrian phasing was used at this intersection.

Alternatives Evaluation

City of Nashua

Purchasing Department
Administrative Services Division (603) 589-3330
229 Main Street - Nashua, NH 03060 Fax (603) 594-3233

January 10, 2022
Memo #22-225

TO: Mayor Donchess
Finance Committee

SUBJECT: Sewer Line Replacement & Building Repairs in the amount not to exceed $98,366 funded
from 81200 Buildings & Improvements/FTA Grant Funds

Please see attached communications from Camille Correa, Transportation Manager, dated January 6, 2022
for project specific details related to this purchase. Below please find a summary of the purchase approval
request:

Item: Waste Line & Building Repairs at the Nashua Transit Administration Building
Value: $98,366
Vendor: Schroeder Construction

Department: 186 Transportation
Source Fund: 81200 Buildings & Improvements/ FTA Grant Funds

Ordinance: Pursuant to § 5-78 Major purchases (greater than $25,000) A. All supplies and
contractual services, except as otherwise provided herein, when the estimated
cost thereof shall exceed $25,000 shall be purchased by formal, written contract
from the lowest responsible bidder, after due notice inviting bids.

A competitive bidding RFP for this project was issued on 9/13/2021 and the following bids were received:

Vendor Location Amount Note
Schroeder Construction Nashua, NH $98,336

The Community Development Division: Transit Department, and the Purchasing Department respectfully
request your approval of this contract.

Regards,
Kelly Parkinson

Purchasing Manager

Ce: C Correa
J Graziano

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Vanasse Hangen Brustlin, Inc.

The overall delay at the Main Street/Park Street/ Water Street intersection shows a
modest improvement with the conversion to two-way operations. This is primarily
due to the shift in vehicle demand from Water Street to Factory Street.

@ 3.1.4 East and West Pearl Street Two-Way Conversion

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The portion of West Pearl Street from Walnut Street to Main Street and East Pearl
Street from Main Street to Temple Street could be transitioned from existing 1-way
westbound to 2-way traffic flow under the East and West Pearl Street 1-way to 2-way
alternative. This alternative is illustrated in Figure 19.

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Figure 19: East and West Pearl Streets Two-way Conversion Alternative

35

This conversion to two-way flow along the entire length of the study area would be
relatively complex due to the varying existing cross section of the pavement width.
The narrowest section is located on East Pearl Street near the Temple Street
intersection where the road is only 28 feet wide. The widest section of the roadway is
on East Pearl Street between Main Street and Spring Street where the cross section is
38 feet wide. The constraints of the existing pavement width would limit the choice
of what new roadway geometry to include; travel lanes in each direction, on-street
parking and bike lanes. Traffic control device modifications would be necessary at
Temple Street/East Pearl Street Main Street/East Pearl Street/West Pearl Street and
West Pearl Street /Walnut Street. Additional minor street intersections would also
need some modifications. These traffic control device modifications include the
following:

> Removal of one-way street and prohibited turn signage at multiple intersections
including Walnut Street/ West Pearl Street, Elm Street /West Pearl Street, East
Pearl Street /Spring Street, East Pearl Street/Cottage Street, East Pearl
Street/Quincy Street, East Pearl Street/Holmes Street, East Pearl Street/Mason
Street, East Pearl Street/White Avenue, and East Pearl Street/Temple
Street /South Street.

» Modification of traffic signal heads on the existing west bound approach at East
Pearl Street’s intersection with Main Street.

» Installation of traffic signal heads for the east bound approach at West Pearl
Street's intersection with Main Street.

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» Traffic signal controller cabinet modifications to provide appropriate traffic
signal phasing for the new geometry at Main Street / West Pearl Street /East Pearl
Street intersection.

Traffic operational analysis shows levels of service to remain the same (LOS C) as the
existing condition for the AM and PM peak hours at the signalized intersection of
Main Street and East/West Pearl Street. This result is based upon a forecast
diversion of approximately 125 vehicles during peak hours. Table 6 summarizes the
traffic operational results compared to the existing condition at the signalized
intersection of Main Street and East/West Pearl Street.

Table 6 - Signalized Intersection Capacity Analysis Summary

2-Way Alternative

(Single Lane E/W
Approaches
Existing 1-Way Conc. Side Street and
(Excl. PED) Excl PED)
vic* Delay** LOS** vic Delay’ LOS
Main St. at East/West Pearl St AM — 0.50 21 c 0.60 28 Cc
PM 0.47 22 Cc 0.56 32 Cc

* Volume to Capacity Ratio.

“* Delay in seconds per vehicle.

“’ Level of Service.

Tt should be noted that the analysis presented in Table 6 includes concurrent side
street phasing and exclusive pedestrian phasing for the traffic signal. This would
need to be reviewed more closely if this alternative is progressed to verify that the
phasing will work from a geometric standpoint and that split phasing can be utilized.

Additionally, the unsignalized side streets where not reviewed in detail for the
consideration of this alternative. These intersections will all experience an increase in
delay as a result of the added conflict movements.

A variation on this alternative could also be considered where either East Pear] Street
only or West Pearl Street only is converted to two way operations.

@ 3.1.5 Factory/Temple Street and East/West Pearl Street

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Under the reverse 1-way Factory/Temple and East/West Pearl Street alternative, the
existing eastbound traffic movements along Factory Street and Temple Street and the
existing westbound traffic movements along East and West Pearl Street would be
reversed. Noted is that the existing Temple Street 2-way traffic flows from Main
Street to Spring Street would also be changed to 1-way westbound. This alternative
is illustrated in Figure 20.

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