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.

2 TRB 86th Annual Meeting - DC 2007

Presentation Outline

Research Objectives

Study Area / Methodologies

Analysis and Results

Conclusions

3 TRB 86th Annual Meeting - DC 2007

Research Objectives

1st Bottleneck Study in Portland

Create a Learning Tool for Students

Measure Capacity on 217

Compare Non/Recurrent Congestion

4 TRB 86th Annual Meeting - DC 2007

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

5 TRB 86th Annual Meeting - DC 2007

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

6 TRB 86th Annual Meeting - DC 2007

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

7 TRB 86th Annual Meeting - DC 2007

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

8 TRB 86th Annual Meeting - DC 2007

Raw Occupancy Plot

9 TRB 86th Annual Meeting - DC 2007

Flow vs. Occupancy

Scholls Ferry Road – February 7, 2006

10 TRB 86th Annual Meeting - DC 2007

Queued and Unqueued States

Scholls Ferry – February 7, 2006

11 TRB 86th Annual Meeting - DC 2007

Flow vs. Occupancy

Greenburg Road – February 7, 2006

12 TRB 86th Annual Meeting - DC 2007

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

13 TRB 86th Annual Meeting - DC 2007

Occupancy Plot

14 TRB 86th Annual Meeting - DC 2007

Results

15 TRB 86th Annual Meeting - DC 2007

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

16 TRB 86th Annual Meeting - DC 2007

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

17 TRB 86th Annual Meeting - DC 2007

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

18 TRB 86th Annual Meeting - DC 2007

Acknowledgements

• ODOT

• Dr. Robert Bertini

• Steve Boice

• Sirisha Kothuri

• TRB reviewers

19 TRB 86th Annual Meeting - DC 2007

Questions?

???