Post on 26-May-2020
PROTECTING THE SILVER LINEFROM CONGESTION IN DUDLEY SQUARE
GUILHERME TOMIYOSHI NAKAO
M.S. CIVIL ENG. - TRANSPORTATION ENG.
ADVISOR: PETER G. FURTH
NORTHEASTERN UNIVERSITY
05/26/2016
Bus lane
Dudley Station
Dedicated
Bus lane
Mixed Traffic Mixed Traffic
AREA OF STUDY
AVL DATA: SILVER LINE 5, PM PEAK
Dudley Station
Avg. Speed:
4.4 mph (6.45 ft/s)
• Avg. Speed: 4.4 mph
• Avg delay: 2.5 min
• 95th-p delay: 4.4 min
Queuing region
Queuing around Dudley Station
Single-lane queuing
Washington St and Warren St junction
Washington St @Ruggles St
Main bottlenecks on Washington St
•@ Ruggles St
•@ Malcolm X Blvd /
Dudley St
• Unsignalized intersection
• Informal priority rules force
SB Washington St traffic to
stop
Wash. St @ Ruggles St
Wash. St @ Ruggles St: Cut-Through traffic
• Insufficient capacity for Phase 1 (30 s
out of 100)
•Many other problems with this signal
• Ped pushbutton = inappropriate
• Long crossing (88 ft – equivalent of 8
lanes)
• Ped phase (26 s) is non-compliant
• Unprotected left turn Dudley-Wash:
unsafe, often blocks a lane
WASH. ST @ MALCOLM X BLVD / DUDLEY ST
• Traffic turning counts
• Signal timings
• Pedestrian Volumes (at crosswalks and between them)
• Bus volumes
• Double Parking
• Bus travel time from AVL
• Modelled on PTV VISSIM
DATA COLLECTION
AVL Data
04/05/16 04/06/16 04/07/16
• Low free-flow speed (19 mph, 13 mph)
• Pedestrians on crosswalks and at dummy crosswalks
• Double parking
• Special priority rules around Ruggles St.
• Occasional single lane queuing in front of Dudley Station
• Buses leaving the station encroach on two lanes and force
their way in
Model features and Calibration
Validation: SL5 Travel time
Proposed changes: Ruggles St
• Change to one-way
westbound from
Washington St to
Shawmut Ave
• Similar to W. Newton,
Concord and Rutland
Streets in the South End
Proposed changes:
Malcolm X Blvd / Dudley St
• Eliminate northbound left turns (<10 veh/h)
• Protected WB left turn
• Concurrent pedestrian Phase every cycle
Geometric changes
• Crossing distance reduced from 88 to 62 ft
• Left turn bay added
PROPOSED SIGNAL TIMING PLAN
• Maintains 100 s coordination along Dudley
• Increased capacity SB
• Ped phases are concurrent, automatic and longer
SL Travel Time: AVL x Base Sim x Proposed changes
0%
10%
20%
30%
40%
50%
60%
70%
80 120 160 200 240 280 320 360 400 440 480 520+
Silver Line Travel time (s) – AVL x Base x Proposed changes
AVL data Base model Proposed changes
Existing (AVL): Mean 229 s; σ = 86 s
Existing (Base Model): Mean 234s; σ =115 s
Proposed: Mean 109 s; σ = 37 s
Contact info
Guilherme Tomiyoshi NakaoMS Civil Eng – Transportation Engineering
Northeastern University
guinakao@gmail.com