Bottleneck Identification on Oregon 217 with PORTAL Data
Zachary HorowitzDavid Evans and Associates
Dr. Robert BertiniPortland State University
TRB 86th Annual MeetingWashington, DC. January 2007.
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Presentation Outline
Research Objectives
Study Area / Methodologies
Analysis and Results
Conclusions
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Research Objectives
1st Bottleneck Study in Portland
Create a Learning Tool for Students
Measure Capacity on 217
Compare Non/Recurrent Congestion
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Study Area - Overview
Oregon Highway 217
• 7 miles long
• North to South trips from US 26 and I-5
• Connects Portland, Beaverton & Tigard
Study Almanac
• Dates: Tuesday-Thursdays, February - May 2006
• Times: 6:00 – 10:00 AM
• Southbound travel direction (towards I-5)
S
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Study Area - Infrastructure
Traffic Data
• Oregon Department of Transportation (ODOT)
• 9 sets of inductive loop detectors, and all on-ramps
• 20-second data aggregation
• Volumes, occupancy and speed (calculated)
• Data retrieved through PORTAL online system located at Portland State University
SouthSouth
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Study Area - Operations
Mainline at 7:00am
• 2 lanes
~ 1900 vehicles/hr/lane
Scholls Ferry On-Ramp
• Metered at 700 vehicles/hr
• Operating at capacity
Greenburg Off-ramp
• Heavy weaving volumes
Geometry
45° bend south of on-ramp
Interchange spacing
Scholls
Fer
ry
Slive.com
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Methodology
• Cumulative counts• Raw 20-sec occupancy• Oblique, transformed curves• Q=KV scatter plot• Speed plots
0
500
1000
1500
2000
2500
7:00 7:15 7:30 7:45 8:00
Time
5021
7:19
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Raw Occupancy Plot
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Flow vs. Occupancy
Scholls Ferry Road – February 7, 2006
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Queued and Unqueued States
Scholls Ferry – February 7, 2006
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Flow vs. Occupancy
Greenburg Road – February 7, 2006
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Speed PlotsHall Blvd – 7:22
0
500
1000
1500
2000
2500
3000
7:00 7:15 7:30 7:45 8:00
Time
V(H
all,t
) -
v0
= 1
22
00
mp
h
5121
7:25
Denney Rd - 7:25
0
500
1000
1500
2000
2500
3000
3500
7:00 7:15 7:30 7:45 8:00
Time
V(A
llen
,t)
- v0 =
13600 m
ph
5621
7:28
Allen Blvd – 7:28
0
500
1000
1500
2000
2500
3000
3500
4000
7:00 7:15 7:30 7:45 8:00
Time
V(B
HH
,t)
- v0 =
14300 m
ph
58 137:35
Beaverton-Hillsdale – 7:35
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Occupancy Plot
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Results
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Congestion Comparison
• Recurrent congestion– Discharge flow: 3,620 vph– Flow drop: 3.9%– Shock speed: 8.8 mph
• Incident-related congestion– Discharge flow: 2,850 vph– Flow drop: 20.4%– Shock speed: 18.2 mph
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Conclusions• Recurrent SB congestion during AM• Flow drop similar to previous studies
Main causes of congestion:• Heavy mainline flow + on-ramp volumes• Substandard geometries along 217• Heavy weaving volumes
Effective operational capacity: 2,000 vphpl
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Future Study
• Collect off-ramp data
• Integration with ramp metering
project
• HCM analyses (weaving, freeway)
• Upgrade loop hardware (direct
speed measurement)
• Freight data collection
• ODOT 217 corridor study
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Acknowledgements
• ODOT
• Dr. Robert Bertini
• Steve Boice
• Sirisha Kothuri
• TRB reviewers
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Questions?
???
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