@ Vanasse Hangen Brustlin, Inc.
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
Cai mmierundiemiia 2 Alternatives Evaluation
Alaport docs:
