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