HomeMy WebLinkAboutProjections and Analysis_201401311823002783TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 36
DESIGN YEAR CONDITIONS
TRAFFIC GROWTH
Traffic volumes on the study area roadways were projected out to a ten-year period for design
purposes. To develop the ten-year forecast, two sources of traffic growth were considered.
First, an annual-average traffic-growth percentage was determined. Based on a review of
historical traffic volume data from the automatic traffic recorders by NP&EDC on the major
roadways within the Mid Island area (provided in the Appendix), an annual growth rate of
approximately 2.0 percent has occurred over the past seven years (1997 to 2004). In addition,
the historical Nantucket Steamship Authority (SSA) automobile, passenger and truck data and
the Nantucket Memorial Airport passenger enplanement data were reviewed. The SSA data
indicated that between 1993 and 2003, the automobiles, passengers and trucks carried have
increased at a rate of approximately 2.1 percent per year. In comparison to the SSA, the
Nantucket Memorial Airport has experienced a higher enplanement rate over the past ten years
(1993 to 2003), with passenger enplanements increasing at a rate of approximately 3.5 percent
per year. However, the enplanement forecast by the Nantucket Memorial Airport for the years
2003 to 2020 anticipates an annual growth rate of approximately three percent. Based on
discussions with town officials, it was agreed that a 3.0 percent per year growth rate is
representative of growth in this area. Therefore, a 3.0 percent compounded annual growth rate
was used in this study.
Second, any planned or approved specific developments in the area that would generate a
significant volume of traffic on study area roadways within the next ten years were included.
Based on discussions with officials from the Town of Nantucket, four developments are
currently planned and/or approved in the immediate area.
The first project involves the potential development of the “Craig Property.” The Craig Family
owns one of the very few large undeveloped parcels of land in the Mid Island Area. This parcel
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 37
is located on the north side of Sanford Road between Sparks Avenue and Pleasant Street. The
following are three potential development scenarios outlined in the Mid-Island Plan prepared by
NP&EDC in March 2003 for this vacant parcel:
1. Expansion of the Boys and Girls Club
This alternative includes the expansion of the existing facility to include a gymnasium on
the north side of the building and playing fields on the south side of the building. This
alternative would also potentially include the construction of the central stop for
Nantucket Regional Transit Authority (NRTA) buses.
2. Playing Fields and Performing Arts/Community Center
This alternative includes the construction of a Performing Arts Center, which could also
serve as a Town meeting space in addition to providing staged performance. This
alternative would also potentially include the NRTA central bus stop as described in
number 1 above.
3. Commercial /Residential Development
This alternative would be to develop the vacant land in accordance with the Mid Island
Plan with buildings consisting of commercial space on the lower levels and housing on
the upper levels, placed close to the street and parking in the rear. The alternative would
also potentially include the NRTA central bus stop as described above.
The second development is the potential relocation of the existing Nantucket Fire Station. The
fire station is presently located on a small parcel of land, adjacent to the Stop & Shop facility,
and cannot meet the future needs of the island within the limits of this site. The Town is
presently evaluating the needs of the Fire Department and has identified the existing Electric
Company site (located at the intersection of Fairgrounds Road and Old South Road) as the
primary location for a new Public Safety Building.
The third development includes the potential expansion of the existing Stop & Shop facility to
include the enhancement of the warehousing capabilities and the produce area of their facility.
Enhancements to its facility also include the expansion of its parking facilities to the east, onto
the property currently occupied by the Nantucket Fire Department. This alternative could
potentially include the construction of the central stop for Nantucket Regional Transit Authority
(NRTA) buses as well as the inclusion of a “liner” building adjacent to the Pleasant Street
sidewalk. This will create more of a downtown feeling with the buildings directly abutting, or
“lining” the sidewalks. In addition, the Mid Island Plan recommends that as part of these
enhancements to the existing facility, the Stop & Shop should consider providing Transportation
Demand Management (TDM) opportunities, such as home shopping service, similar to the
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 38
“Peapod” service it established in the Boston area, and providing employee housing on the upper
level of its expanded area.
The fourth development includes the potential relocation of the existing deficient post office
facility, currently located on the northwest corner of Pleasant Street and Daves Street to the
parcel of land currently serving as a boat yard on the west side of the Pacific Bank, near the
intersection of Sparks Avenue and Pleasant Street.
In addition to the four aforementioned potential developments, based on discussions with town
officials, there is the potential for development of 13 additional parcels of existing vacant land in
the immediate area. There were five high priority and five medium priority parcels of land
identified off of Old South Road between Forest Avenue and Bunker Road, one medium priority
parcel located on Bartlett Road west of Mizzenmast Road, one high priority parcel located on
Surfside Road south of Windy Way, and one high priority parcel located on Polpis Road, just
north of Milestone Road. These developments have the potential for light commercial, retail or
residential uses. Given the uncertainty for these 13 potential developments, along with the
aforementioned four potential developments coupled with limits for growth of an island, it was
agreed with Town officials that all the aforementioned potential developments would be
included as part of the conservative 3.0 percent annual traffic growth rate.
Design year (2014) weekday AM, weekday PM, and Saturday midday peak hours were
developed by applying a compounded 3.0 percent annual growth rate (or 34.4 percent
compounded over ten years) to the existing volumes. The Design Year peak-hour traffic
volumes are shown on Figures 13 to 15 for the weekday AM, weekday PM and Saturday midday
peak hours, respectively.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 42
PLANNED ROADWAY IMPROVEMENTS
Based on discussions with officials from the Town of Nantucket, there is one roadway
improvement project planned in the study area. The Sparks Avenue at Pleasant Street and
Hooper Farm Road Intersection Improvement Project is currently under design. Improvements
to this intersection include the reconstruction of the intersection to a modern single lane
roundabout, consistent with national standards (FHWA Roundabout Design Guidelines). The
proposed design will provide continuous traffic flow through the intersection and consists of
reconstructing and realigning the four approaches to intersect at approximately 90 degrees at a
modern roundabout. Eight-foot wide crosswalks will be provided across each intersection
approach, with 5-foot wide sidewalks and wheelchair compliant ramps along both sides of each
roadway, with the exception of the south side of Sparks Avenue where 8-foot wide multi-use
paths will be provided. A 14-foot wide mountable apron will be provided at the outer edge of
the 40-feet inner diameter central island (for a total central island diameter of 68 feet), providing
additional paved area to allow for over-tracking of large trucks, but discouraging passenger
vehicle travel. While it is hopeful that construction will begin in 2005, the project is currently
under review by MassHighway at the 100 percent design stage and, therefore; the timing of
construction is dependent on the scheduling of MassHighway. This intersection was analyzed
both with and without the aforementioned improvements under both 2004 Existing and 2014
Design year conditions for comparison purposes, to demonstrate the benefits of the proposed
roundabout and is included in the Analysis section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 43
ANALYSIS
CAPACITY ANALYSIS METHODOLOGY
A primary result of capacity analysis is the assignment of levels of service to traffic facilities
under various traffic flow conditions. The capacity analysis methodology is based on the
concepts and procedures in the Highway Capacity Manual (HCM).2 The concept of level of
service (LOS) is defined as a qualitative measure describing operational conditions within a
traffic stream and their perception by motorists and/or passengers. A level-of-service definition
provides an index to quality of traffic flow in terms of such factors as speed, travel time, freedom
to maneuver, traffic interruptions, comfort, convenience, and safety.
Six levels of service are defined for each type of facility. They are given letter designations from
A to F, with LOS A representing the best operating conditions and LOS F the worst. Since the
level of service of a traffic facility is a function of the traffic flows placed upon it, such a facility
may operate at a wide range of levels of service, depending on the time of day, day of week, or
period of year. A description of the operating condition under each level of service is provided
below:
LOS A describes conditions with little to no delay to motorists.
LOS B represents a desirable level with relatively low delay to motorists.
LOS C describes conditions with average delays to motorists.
LOS D describes operations where the influence of congestion becomes more noticeable.
Delays are still within an acceptable range.
2Highway Capacity Manual 2000, Transportation Research Board; Washington, D.C.; 2000.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 44
LOS E represents operating conditions with high delay values. This level is considered
by many agencies to be the limit of acceptable delay.
LOS F is considered to be unacceptable to most drivers with high delay values that often
occur, when arrival flow rates exceed the capacity of the intersection.
Unsignalized Intersections
Levels of service for unsignalized intersections are calculated using the operational analysis
methodology of the HCM. The procedure accounts for lane configuration on both the minor and
major street approaches, conflicting traffic stream volumes, and the type of intersection control
(STOP, YIELD, or all-way STOP control). The definition of level of service for unsignalized
intersections is a function of average control delay. Control delay includes initial deceleration
delay, queue move-up time, stopped delay, and final acceleration delay. The level-of-service
criteria for unsignalized intersections are shown in Table 3.
Roundabout Analysis
Roundabout (or rotary) capacity analysis is based on the concepts and procedures described in
the Signalized and Unsignalized Intersection Design and Research Aid (aaSIDRA).3 The main
features of the aaSIDRA method for roundabout capacity estimation are the dependence of gap
acceptance parameters on roundabout geometry, circulating flows and entry lane flows, and the
designation of approach lanes as dominant and subdominant lanes that have different capacity
characteristics. The aaSIDRA output produces level-of-service results based on the concepts
described in the HCM. The level-of-service criteria for roundabouts are the same as for
signalized intersections as shown in Table 3.
3 Signalized & Unsignalized Intersection Design & Research Aid, aaSIDRA 2.0 Version 2.0.3.217; Akcelik &
Associates Pty Ltd, Greythorn, Victoria, Australia; 2002.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 45
Table 3
LEVEL-OF-SERVICE CRITERIA FOR INTERSECTIONS
Level of Service
Unsignalized Intersection Criteria
Average Control Delay
(Seconds per Vehicle)
Signalized Intersection and
Roundabout Criteria
Average Control Delay
(Seconds per Vehicle)
A ≤10 ≤10
B >10 and ≤15 >10 and ≤20
C >15 and ≤25 >20 and ≤35
D >25 and ≤35 >35 and ≤55
E >35 and ≤50 >55 and ≤80
F >50 >80
Source: Highway Capacity Manual 2000, Transportation Research Board; Washington, D.C.; 2000. Pages 10-16 and 17-2.
QUEUE ANALYSIS METHODOLOGY
For unsignalized intersections, the 95th percentile queue represents the length of queue of the
critical minor-street movement that is not expected to be exceeded 95 percent of the time during
the analysis period (typically one hour). In this case, the queue length is a function of the
capacity of the movement and the movement’s degree of saturation.
ANALYSIS RESULTS
The following tables and discussion illustrate the results of the analysis performed on existing
2004 volumes and projected 2014 volumes under the existing geometric configurations. All
locations were analyzed in accordance with the above methodology and are summarized in
Tables 4 to 19. All analysis worksheets are provided in the Appendix.
Milestone Road at Polpis Road
Under both 2004 Existing and 2014 Design Year conditions, left-turns from Milestone Road
onto Polpis Road operate at acceptable LOS B or better during the weekday AM, weekday PM
and Saturday midday peak hours. In addition, there is sufficient roadway width on Milestone
Road to allow through vehicles to bypass left turning vehicles. Left- and right-turning
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 46
movements from Polpis Road onto Milestone Road are projected to operate with capacity
constraints (LOS E/F) under future traffic-volume conditions during all three peak hours studied.
In addition, the accident records indicate a safety issue at this intersection due to the existing
geometric issues, the numerous merging and conflict points. Improvements are recommended at
this location to improve overall intersection operation and safety, as described in the
Findings/Recommendations section of this report.
Table 4
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Milestone Road at Polpis Road
2004 Existing 2014 Design Year
Milestone Road at Polpis Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Milestone Rd EB left turns
Polpis Rd SB left turns
Polpis Rd SB right turns
Weekday PM:
Milestone Rd EB left turns
Polpis Rd SB left turns
Polpis Rd SB right turns
Saturday Midday:
Milestone Rd EB left turns
Polpis Rd SB left turns
Polpis Rd SB right turns
0.25
0.44
0.52
0.31
0.90
0.90
0.28
0.64
0.55
9.6
53.4
17.4
10.1
161.2
43.6
9.4
82.7
17.2
A
F
C
B
F
E
A
F
C
25
48
75
34
121
266
29
80
84
0.39
1.41
0.86
0.49
3.48
1.51
0.43
2.14
0.89
11.5
388.3
43.4
13.0
NC
265.7
11.3
772.0
43.8
B
F
E
B
F
F
B
F
E
48
172
224
68
305
909
54
246
252
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
NC = No capacity available.
Milestone Road at Monomoy Road
Under both 2004 Existing and 2014 Design Year conditions, left-turns from Milestone Road
onto Monomoy Road operate at acceptable LOS B or better during the weekday AM, weekday
PM and Saturday midday peak hours. In addition, there is sufficient roadway width on
Milestone Road to allow through vehicles to bypass left turning vehicles. Left-turning
movements from Monomoy Road onto Milestone Road are projected to operate with capacity
constraints (LOS E/F) during all three peak hours studied, along with right-turning movements
during the weekday PM peak hour under future traffic-volume conditions. Improvements are
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 47
recommended at this location to improve overall intersection operation and safety, as described
in the Findings/Recommendations section of this report.
Table 5
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Milestone Road at Monomoy Road
2004 Existing 2014 Design Year
Milestone Road at Monomoy Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Milestone Rd EB left turns
Monomoy Rd SB left turns
Monomoy Rd SB right turns
Weekday PM:
Milestone Rd EB left turns
Monomoy Rd SB left turns
Monomoy Rd SB right turns
Saturday Midday:
Milestone Rd EB left turns
Monomoy Rd SB left turns
Monomoy Rd SB right turns
0.07
0.14
0.14
0.12
0.60
0.37
0.06
0.11
0.11
9.7
40.2
15.4
12.3
160.4
31.3
9.2
35.7
14.3
A
E
C
B
F
D
A
E
C
5
12
12
10
56
40
4
9
9
0.11
0.43
0.26
0.23
2.71
0.88
0.09
0.30
0.20
11.2
114.1
22.2
17.1
NC
118.7
10.4
87.0
19.3
B
F
C
C
F
F
B
F
C
10
40
25
22
139
136
8
26
19
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
NC = No capacity available.
Milestone Rotary
As shown in Table 6, under 2004 Existing conditions all approaches at the Milestone Rotary
operate at acceptable LOS (LOS D or better) during the weekday AM, weekday PM and
Saturday midday peak hours. However, under 2014 conditions, the Sparks Avenue and Old
South Road approaches will operate with capacity constraints and long delays (LOS F) during
the peak hours. While longer-term improvements of this location will require further study,
short-term improvements are offered within the Findings/Recommendations section that better
define right-of-way through the rotary.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 48
Table 6
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Milestone Rotary
2004 Existing 2014 Design Year
Milestone Rotary V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Sparks Ave EB approach
Old South Rd NB approach
Milestone Rd WB approach
Orange St SB approach
Weekday PM:
Sparks Ave EB approach
Old South Rd NB approach
Milestone Rd WB approach
Orange St SB approach
Saturday Midday:
Sparks Ave EB approach
Old South Rd NB approach
Milestone Rd WB approach
Orange St SB approach
0.67
0.79
0.51
0.36
0.82
0.89
0.58
0.50
0.82
0.92
0.49
0.47
11.3
19.8
8.8
6.7
26.0
31.8
9.3
8.0
21.4
36.1
8.4
7.1
B
B
A
A
C
C
A
A
C
D
A
A
188
328
102
48
305
495
128
80
305
542
92
75
1.23
1.27
0.73
0.55
1.91
1.23
0.80
0.80
1.73
1.23
0.68
0.72
136.6
151.5
13.8
9.1
453.8
134.5
15.4
14.7
363.8
136.7
12.3
11.3
F
F
B
A
F
F
B
B
F
F
B
B
1,500
1,852
220
92
2,742
1,800
288
202
2,785
1,822
185
168
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Sparks Avenue at Pleasant Street and Hooper Farm Road
As shown in Table 7, under both 2004 Existing and 2014 Design Year conditions, without
improvements, the Hooper Farm northbound, the Pleasant Street southbound and the Sparks
Avenue eastbound approaches operate with long delays and queues (LOS F). Intersection
improvements to provide a single lane roundabout at this location are proposed under a separate
study, as described in the Design Year Conditions section of this report. The proposed
improvements under both 2004 Existing and 2014 Design Year conditions will bring this
intersection up to an acceptable LOS (LOS A/B) and provide improved traffic operations, with
shorter vehicle queue lengths.
TRAFFIC STUDY Mid-Island Area, Nantucket, Massachusetts Final Report Page 49 Table 7 INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY Sparks Avenue at Pleasant Street and Hooper Farm Road 2004 Existing 2004 Existing with Planned Intersection Improvements 2014 Design Year 2014 Design Year with Planned Intersection Improvements Sparks Avenue at Pleasant Street and Hooper Farm Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue V/CDelay LOSQueueV/CDelayLOSQueue Weekday AM: Pleasant St SB approach Sparks Ave EB approach Hooper Farm Road NB approach Sparks Ave WB approach Weekday PM: Pleasant St SB approach Sparks Ave EB approach Hooper Farm Road NB approach Sparks Ave WB approach Saturday Midday: Pleasant St SB approach Sparks Ave EB approach Hooper Farm Road NB approach Sparks Ave WB approach 0.901.241.850.391.021.341.610.331.181.441.960.35 67.3 276.7 833.9 0.0 116.3 362.1 632.3 0.0 216.5 444.4 947.0 0.0 F F F A F F F A F F F A 2751,4322,34805851,9501,61501,1882,1622,44000.28 0.360.370.520.320.450.280.420.360.450.360.44 11.4 9.5 12.9 9.4 12.0 10.4 11.1 9.5 12.7 10.6 11.8 9.2 B A B A B B B A B B B A 55 68 70 110 65 88 50 82 75 85 68 90 1.752.575.070.522.002.754.520.442.253.025.550.47729.6NCNC0.0900.1NCNC0.0NCNCNC0.0 F F F A F F F A F F F A 2,7005,0985,47003,7525,8924,29804,7605,9625,4700 0.44 0.55 0.57 0.75 0.49 0.71 0.47 0.62 0.55 0.71 0.61 0.66 14.3 11.6 16.7 12.4 13.3 17.9 14.5 10.4 14.8 18.2 19.3 10.6 B B B B B B B B B B B B 8812814025510523595145135228160172 aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle). NC = No capacity available.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 50
Orange Street at West Creek Road
As illustrated in Table 8, under both 2004 Existing and 2014 Design Year conditions, left-turns
from Orange Street onto West Creek Road operate at acceptable LOS B or better during the
weekday AM, weekday PM and Saturday midday peak hours. Left- and right-turning
movements from West Creek Road onto Orange Street operate with long delays and queues
(LOS F) under both 2004 Existing and 2014 Design Year conditions during all three peak hours
studied.
Table 8
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Orange Street at West Creek Road
2004 Existing 2014 Design Year
Orange Street at West Creek Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Orange St NB left turns
West Creek Rd EB approach
Weekday PM:
Orange St NB left turns
West Creek Rd EB approach
Saturday Midday:
Orange St NB left turns
West Creek Rd EB approach
0.05
1.00
0.05
1.06
0.06
1.08
8.7
97.0
9.3
121.2
9.5
134.3
A
F
A
F
A
F
4
244
4
259
5
258
0.08
2.33
0.08
2.61
0.11
2.82
9.4
666.9
10.4
804.2
10.8
907.9
A
F
B
F
B
F
6
730
6
729
9
709
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Pleasant Street at West Creek Road
As illustrated in Table 9,under both 2004 Existing and 2014 Design Year conditions, left-turns
from Pleasant Street onto West Creek Road operate at acceptable LOS B or better during all
three peak hours studied. Left- and right-turning movements from West Creek Road onto
Pleasant Street operate at LOS C under 2004 Existing conditions during all three peak hours
studied. Under 2014 Design Year conditions, the West Creek Road turning movements
deteriorate to LOS E during the weekday AM peak hour and LOS F during both the weekday
PM and Saturday midday peak hours. Improvements are recommended at this location to
improve overall intersection operation and safety, as described in the
Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 51
Table 9
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Pleasant Street at West Creek Road
2004 Existing 2014 Design Year
Pleasant Street at West Creek Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Pleasant St SB left turns
West Creek Rd WB approach
Weekday PM:
Pleasant St SB left turns
West Creek Rd WB approach
Saturday Midday:
Pleasant St SB left turns
West Creek Rd WB approach
0.15
0.35
0.18
0.45
0.18
0.45
9.1
18.7
9.3
23.7
9.3
24.4
A
C
A
C
A
C
14
39
17
56
16
56
0.24
0.73
0.29
1.02
0.28
1.02
10.3
47.9
10.8
117.1
10.8
117.4
B
E
B
F
B
F
23
128
30
227
28
222
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Pleasant Street at Cherry Street, Williams Lane and Williams Street
As shown in Table 10, acceptable operating conditions (LOS D or better) are experience for all
turning movements at the unsignalized intersections of Pleasant Street at Cherry, Williams Lane
and Williams Street under both 2004 Existing and 2014 Design Year conditions during the
weekday AM, weekday PM and Saturday midday peak hours. However, the accident records
indicate a safety issue at these intersections due to the existing geometric deficiencies.
Improvements are recommended at this location to improve overall intersection operation and
safety, as described in the Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 52
Table 10
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Pleasant Street at Cherry Street, Williams Lane and Williams Street
2004 Existing 2014 Design Year
Intersection/Peak Hour/Movement V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Pleasant Street at Cherry Street
Weekday AM:
Pleasant St SB left turns
Cherry St Rd WB approach
Weekday PM:
Pleasant St SB left turns
Cherry St Rd WB approach
Saturday Midday:
Pleasant St SB left turns
Cherry St Rd WB approach
Pleasant Street at Williams Lane
Weekday AM:
Pleasant St NB left turns
Williams Ln EB approach
Weekday PM:
Pleasant St NB left turns
Williams Ln EB approach
Saturday Midday:
Pleasant St NB left turns
Williams Ln EB approach
Pleasant Street at Williams Street
Weekday AM:
Williams St WB approach
Weekday PM:
Williams St WB approach
Saturday Midday:
Williams St WB approach
0.09
0.05
0.08
0.07
0.06
0.13
0.07
0.27
0.11
0.20
0.14
0.23
0.34
0.33
0.32
9.0
13.9
9.0
17.7
9.3
17.2
8.1
12.4
8.5
12.6
8.5
13.2
17.1
17.1
17.6
A
B
A
C
A
C
A
B
A
B
A
B
C
C
C
7
4
6
6
5
11
6
28
10
18
12
23
38
36
34
0.14
0.10
0.12
0.17
0.10
0.27
0.11
0.46
0.17
0.34
0.21
0.43
0.63
0.62
0.61
10.1
18.5
10.1
28.5
10.5
27.4
8.6
17.1
9.3
16.8
9.2
19.7
32.6
32.7
34.1
B
C
B
D
B
D
A
C
A
C
A
C
D
D
D
12
9
10
15
8
26
9
60
16
38
19
52
100
97
93
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Orange Street at Union Street
As illustrated in Table 11, under 2004 Existing conditions, left-turns from Orange Street onto
Union Street operate at acceptable LOS D or better during the weekday AM, weekday PM and
Saturday midday peak hours. Under 2014 Design Year conditions, this movement deteriorates to
a LOS D during the weekday AM and Saturday Midday peak hours and LOS F during the
weekday PM peak hour. Left-turning movements from Union Street onto Orange Street are
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 53
projected to operate with capacity constraints (LOS F) under future traffic-volume conditions
during the weekday PM and Saturday midday peak hours. Improvements are recommended at
this location to improve overall intersection operation and safety, as described in the
Findings/Recommendations section of this report.
Due to discrepancies between the data collected as part of this study and past historical data, it is
recommended that this location be further studied based on 2005 summer traffic levels.
Table 11
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Orange Street at Union Street
2004 Existing 2014 Design Year
Orange Street at Union Street V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Orange St SB left turns
Union St WB lefts
Weekday PM:
Orange St SB left turns
Union St WB lefts
Saturday Midday:
Orange St SB left turns
Union St WB lefts
0.16
0.73
0.33
1.26
0.25
1.21
13.4
22.8
19.8
152.1
12.0
130.6
B
D
C
F
B
F
118
225
245
1,020
158
1,000
0.24
1.35
0.58
2.54
0.37
2.36
28.5
193.9
62.8
727.1
28.0
638.5
D
F
F
F
D
F
250
1,135
508
2,958
365
2,998
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Five Corners
As shown in Table 12, under 2004 Existing conditions, the Five Corners all-way STOP
controlled intersection already operates with capacity constraints, with the Pleasant Street
northbound approach operating at LOS E/F during all peak hours studied. These long delays and
queues will be exacerbated with the addition of future growth. However, due to the historical
nature of this location major geometric or operational modifications are not feasible. In addition,
the accident records indicate a safety issue at this intersection due to the existing geometric
issues, the numerous approaches and vast amount of pavement. However, minor improvements
are described in the Findings/Recommendations section of this report to provide better definition
of right-of-way and improve pedestrian access through the intersection.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 54
Table 12
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Pleasant Street at York Street and Atlantic Avenue
2004 Existing 2014 Design Year Pleasant Street
at York Street and Atlantic Avenue V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
York St/Atlantic Ave EB approach
York St WB approach
Pleasant St NB approach
Pleasant St SB approach
Weekday PM:
York St/Atlantic Ave EB approach
York St WB approach
Pleasant St NB approach
Pleasant St SB approach
Saturday Midday:
York St/Atlantic Ave EB approach
York St WB approach
Pleasant St NB approach
Pleasant St SB approach
0.76
0.41
1.00
0.39
0.72
0.45
0.91
0.41
0.64
0.48
1.00
0.40
27.8
14.6
77.5
13.8
22.7
15.0
42.2
13.8
20.8
16.4
76.1
14.0
D
B
F
B
C
C
E
B
C
C
F
B
169
48
370
45
147
57
271
49
112
63
370
48
1.00
0.55
1.00
0.51
1.00
0.66
1.00
0.58
0.96
0.73
1.00
0.59
101.5
20.9
326.9
19.4
92.5
26.3
254.7
22.6
59.4
30.0
367.9
22.4
F
C
F
C
F
D
F
C
F
D
F
C
354
81
428
70
342
116
395
90
289
146
429
91
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Four Corners
As shown in Table 13, under 2004 Existing conditions, the Four Corners all-way STOP
controlled intersection already operates with capacity constraints, with the Surfside Road
approach operating at LOS E/F during all peak hours studied and the Sparks Avenue approach
operating at LOS E during the weekday PM peak hour. These long delays and queues will be
exacerbated with the addition of future growth. Improvements are recommended at this location
to improve overall intersection operation and safety, as described in the
Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 55
Table 13
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Sparks Avenue at Prospect Street, Surfside Road and Atlantic Avenue
2004 Existing 2014 Design Year Sparks Avenue at Prospect Street,
Surfside Road and Atlantic Avenue V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Prospect St EB approach
Sparks Ave WB approach
Surfside Rd NB approach
Atlantic Ave SB approach
Weekday PM:
Prospect St EB approach
Sparks Ave WB approach
Surfside Rd NB approach
Atlantic Ave SB approach
Saturday Midday:
Prospect St EB approach
Sparks Ave WB approach
Surfside Rd NB approach
Atlantic Ave SB approach
0.84
0.81
0.91
0.44
0.83
0.87
0.90
0.61
0.81
0.79
0.95
0.52
33.5
31.5
43.6
16.5
32.9
39.4
42.6
20.9
31.7
31.0
52.2
18.4
D
D
E
C
D
E
E
C
D
D
F
C
207
188
264
53
200
224
251
97
189
175
297
72
1.00
1.00
1.00
0.59
1.00
1.00
1.00
0.83
1.00
1.00
1.00
0.72
159.7
136.2
228.3
26.1
157.4
197.2
228.3
46.6
146.9
131.2
281.0
34.1
F
F
F
D
F
F
F
E
F
F
F
D
351
337
378
90
338
345
364
187
340
328
387
133
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Surfside Road at Vesper Lane
As illustrated in Table 14, under both 2004 Existing and 2014 Design Year conditions, left-turns
from Surfside Road onto Vesper Lane operate at acceptable LOS B or better during the weekday
AM, weekday PM and Saturday midday peak hours. Turning movements from Vesper Lane
onto Surfside Road operate with capacity constraints (LOS E/F) under both existing and future
traffic-volume conditions during all three peak hours studied. Improvements at the adjacent
Four Corners intersection are recommended and are anticipated to improve operations at this
intersection. In addition, traffic calming and safety improvements are recommended for the
Surfside Road intersections and are described in the Findings/Recommendations section of this
report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 56
Table 14
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Surfside Road at Vesper Lane
2004 Existing 2014 Design Year
Surfside Road at Vesper Lane V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Surfside Rd NB left turns
Vesper Ln EB approach
Weekday PM:
Surfside Rd NB left turns
Vesper Ln EB approach
Saturday Midday:
Surfside Rd NB left turns
Vesper Ln EB approach
0.14
0.67
0.09
0.84
0.06
0.75
8.8
40.7
9.1
57.6
8.8
44.6
A
E
A
F
A
E
12
110
8
178
5
144
0.21
1.53
0.15
1.84
0.10
1.59
9.7
316.9
10.2
442.2
9.6
330.4
A
F
B
F
A
F
20
411
13
604
8
514
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Surfside Road at Bartlett Road
As illustrated in Table 15, under both 2004 Existing and 2014 Design Year conditions, left-turns
from Surfside Road onto Bartlett Road operate at acceptable LOS B or better during the weekday
AM, weekday PM and Saturday midday peak hours. Turning movements from Bartlett Road
onto Surfside Road operate with capacity constraints (LOS E/F) under future traffic-volume
conditions during all three peak hours studies. Traffic calming and safety improvements are
recommended for the Surfside Road intersections and are described in the
Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 57
Table 15
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Surfside Road at Bartlett Road
2004 Existing 2014 Design Year
Surfside Road at Bartlett Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Surfside Rd NB left turns
Bartlett Rd EB approach
Weekday PM:
Surfside Rd NB left turns
Bartlett Rd EB approach
Saturday Midday:
Surfside Rd NB left turns
Bartlett Rd EB approach
0.12
0.61
0.20
0.66
0.24
1.00
8.4
26.7
8.8
33.4
9.1
84.5
A
D
A
D
A
F
10
99
18
111
23
287
0.18
1.22
0.29
1.49
0.36
2.40
9.1
164.2
9.8
285.4
10.5
683.7
A
F
A
F
B
F
16
390
31
466
42
966
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Surfside Road at Miacomet Avenue
As illustrated in Table 16, under both 2004 Existing and 2014 Design Year conditions, left-turns
from Surfside Road onto Miacomet Avenue operate at acceptable LOS B or better during all
three peak hours studied. Left- and right-turning movements from Miacoment Avenue onto
Surfside Road operate at LOS C under 2004 Existing conditions during all three peak hours
studied. Under 2014 Design Year conditions, the Miacomet Avenue turning movements
deteriorate to LOS E during the weekday AM peak hour and LOS F during both the weekday
PM and Saturday midday peak hours. In addition, the accident records indicate a safety issue at
this intersection due to the existing geometric issues, the presence of adjacent parking and
driveways, large pavement areas and poorly defined right-of-way. Improvements are
recommended at this location to improve overall intersection operation and safety, as described
in the Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 58
Table 16
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Surfside Road at Miacomet Avenue
2004 Existing 2014 Design Year
Surfside Road at Miacomet Avenue V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Surfside Rd NB left turns
Miacomet Ave EB approach
Weekday PM:
Surfside Rd NB left turns
Miacomet Ave EB approach
Saturday Midday:
Surfside Rd NB left turns
Miacomet Ave EB approach
0.02
0.28
0.08
0.37
0.04
0.38
8.3
18.5
9.0
24.5
8.8
23.8
A
C
A
C
A
C
2
28
6
41
3
42
0.04
0.56
0.12
0.85
0.06
0.82
8.8
36.0
10.0
88.0
9.5
75.6
A
E
B
F
A
F
3
77
10
148
5
144
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Surfside Road at Miacomet Road and Surfside Drive
As illustrated in Table 17, under both 2004 Existing and 2014 Design Year conditions,
northbound and southbound left-turns from Surfside Road onto Miacomet Road and Surfside
Drive, respectively, operate at acceptable LOS A during all three peak hours studied. Turning
movements from the Surfside Drive westbound approach operate at acceptable LOS D or better
during all three peak hours studied under 2004 Existing conditions and deteriorate to LOS E
during the weekday AM peak hour and LOS F during both the weekday PM and Saturday
midday peak hours. Under 2004 Existing conditions, turning movements from the Miacomet
Road eastbound approach operate at LOS C, F and D during the weekday AM, weekday PM and
Saturday midday peak hours, respectively. Under 2014 Design Year conditions, the Miacomet
Road turning movements are expected to deteriorate to LOS E and F during the weekday AM
peak hour and Saturday midday peak hours, and continue to operate at LOS F during the
weekday PM peak hour. Traffic calming and safety improvements are recommended for the
Surfside Road intersections and are described in the Findings/Recommendations section of this
report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 59
Table 17
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Surfside Road at Miacomet Road and Surfside Drive
2004 Existing 2014 Design Year Surfside Road
at Miacomet Road and Surfside Drive V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Surfside Rd NB approach
Surfside Rd SB approach
Surfside Dr WB approach
Miacomet Rd EB approach
Weekday PM:
Surfside Rd NB approach
Surfside Rd SB approach
Surfside Dr WB approach
Miacomet Rd EB approach
Saturday Midday:
Surfside Rd NB approach
Surfside Rd SB approach
Surfside Dr WB approach
Miacomet Rd EB approach
0.01
0.09
0.29
0.23
0.02
0.11
0.58
0.59
0.02
0.07
0.52
0.32
8.0
8.1
14.7
21.4
8.2
8.6
29.0
53.9
8.2
8.3
24.5
28.3
A
A
B
C
A
A
D
F
A
A
C
D
1
7
29
21
2
9
86
79
2
6
72
34
0.01
0.12
0.54
0.53
0.03
0.17
1.42
2.76
0.04
0.10
1.17
0.99
8.3
8.5
25.3
49.4
8.7
9.4
264.5
680.9
8.7
8.8
158.3
164.5
A
A
D
E
A
A
F
F
A
A
F
F
1
11
76
66
3
15
399
319
3
8
315
152
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Surfside Road at Fairgrounds Road
The major (Surfside Road) movements at this unsignalized intersection operate at desirable LOS
A under both existing and future traffic volume conditions during the weekday AM, weekday
PM and Saturday midday peak hours. However, as illustrated in Table 18, the minor
(Fairgrounds Road) movements are expected to operate with capacity constraints (LOS E/F)
under 2014 Design Year conditions during all three peak hours studies. In addition, the accident
records indicate a safety issue at this intersection due to the existing sight distance deficiencies.
Traffic calming and safety improvements are recommended for the Surfside Road intersections
and are described in the Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 60
Table 18
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Surfside Road at Fairgrounds Road
2004 Existing 2014 Design Year
Surfside Road at Fairgrounds Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Surfside Rd NB approach
Surfside Rd SB approach
Fairgrounds Rd WB approach
Fairgrounds Rd EB approach
Weekday PM:
Surfside Rd NB approach
Surfside Rd SB approach
Fairgrounds Rd WB approach
Fairgrounds Rd EB approach
Saturday Midday:
Surfside Rd NB approach
Surfside Rd SB approach
Fairgrounds Rd WB approach
Fairgrounds Rd EB approach
0.00
0.16
0.37
0.46
0.01
0.19
0.86
0.63
0.00
0.11
0.78
0.36
7.4
8.2
16.6
31.7
7.8
8.6
57.3
64.6
8.4
8.0
36.9
28.8
A
A
C
D
A
A
F
F
A
A
E
D
0
14
42
56
1
18
197
84
0
10
170
38
0.00
0.23
0.77
1.06
0.02
0.28
2.38
2.28
0.00
0.16
1.57
0.93
7.5
8.6
46.0
155.7
8.0
9.5
682.9
747.7
8.7
8.4
305.0
131.1
A
A
E
F
A
A
F
F
A
A
F
F
0
22
150
203
1
29
799
309
0
14
680
148
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
Old South Road at Fairgrounds Road
As illustrated in Table 19, under both 2004 Existing and 2014 Design Year conditions, left-turns
from Old South Road onto Fairgrounds Road operate at acceptable LOS B or better during the
weekday AM and PM and Saturday midday peak hours. Left- and right-turning movements
from Fairgrounds Road onto Old South Road operate at LOS F under both 2004 Existing and
2014 Design Year conditions, during all three peak hours studied. In addition, the accident
records indicate a safety issue at this intersection due to the heavy turning volumes and poorly
defined lanes. Improvements are recommended at this location to improve overall intersection
operation and safety, as described in the Findings/Recommendations section of this report.
TRAFFIC STUDY
Mid-Island Area, Nantucket, Massachusetts
Final Report Page 61
Table 19
INTERSECTION CAPACITY AND QUEUE ANALYSIS SUMMARY
Old South Road at Fairgrounds Road
2004 Existing 2014 Design Year
Old South Road at Fairgrounds Road V/Ca Delayb LOSc Queued V/C Delay LOS Queue
Weekday AM:
Old South Rd NB through-lefts
Fairgrounds Rd EB approach
Weekday PM:
Old South Rd NB through-lefts
Fairgrounds Rd EB approach
Saturday Midday:
Old South Rd NB through-lefts
Fairgrounds Rd EB approach
0.15
1.25
0.25
1.98
0.19
1.18
9.4
180.4
10.5
507.2
9.8
156.3
A
F
B
F
A
F
13
402
24
648
17
342
0.23
3.20
0.41
6.51
0.31
3.15
10.8
NC
13.7
NC
11.8
NC
B
F
B
F
B
F
23
1,055
51
1,289
33
945
aVolume-to-capacity ratio. bAverage stopped delay in seconds per vehicle. cLevel of service. d95th percentile queue length in feet per lane (assuming 25 feet per vehicle).
NC = No capacity available.