USING PeMS DATA TO EMPIRICALLY DIAGNOSE FREEWAY BOTTLENECK LOCATIONS

IN ORANGE COUNTY, CALIFORNIA

Robert L. BertiniPortland State University

Aaron M. MytonOregon Department of

Transportation

TRB 84th Annual Meeting

Washington D.C.

January 9-13, 2005

Objectives

• Identify Freeflow Congested Conditions

• Determine Bottleneck Locations

• Measure Queue Discharge Features

• Conclusions

• Foundation for Understanding Freeway Operations

• Queues Cause Delays

• Loop Detectors Good Data Source

• Previous Studies– Throughput Increase 2-5% Prior To Queue

– Diverge Bottleneck Identified

• PeMS Provides Opportunity for Detailed Data Analysis

Background

Cul

ver D

r.

Uni

vers

ity D

r.

Sand

Can

yon

Ave

.

Hw

y. 1

33

Irvin

e C

ente

r Dr.

Trav

el D

irect

ion

130

110

100

90 80 70 60 50 40 30 20 10

Site Map Loop DetectorStation Number

L E G E N D

110

120

• Four Northbound Lanes

• One Northbound HOV Lane

• Freeway Ramps Between Stations, Except 100/110

140

N

Post-mile

Bottleneck Definition

Queued Unqueued

Bottleneck

D e te c to rs

• Queue upstream

• Freely-flowing traffic downstream

• Temporally and spatially variable

Data• Freeway Performance Monitoring System (PeMS)

– http://pems.eecs.berkeley.edu/Public

• Single Inductive Loops

• Vehicle Occupancy and Count

• Data Aggregated in 30-sec. Intervals

• On-Ramp/Off-Ramp Data Not Available

• Monday June 1, 1998

Methodology• Cumulative Curves – Vehicle Count & Occupancy

• Oblique Plots N and T

Analysis

Time, t

Culver Dr.

University Dr.

Sand Canyon Ave.

Hwy. 133

Irvine Center Dr.

Travel Direction

0.60

1.60

2.60

3.60

4.60

5.60

7:00 7:30 8:00 8:30 9:00

Po

st m

ile

Station140

130120

110100

9080

70

60

50

40

30

20

10

-53500

-53000

-52500

-52000

-51500

-51000

-505007:

00

8:00

9:00Time, t

N(7

0,t)

- q0t

', q

0 =

9500

vph

-14000

-13800

-13600

-13400

-13200

-13000

-12800

-12600

T(70

,t) -

b0t

', b

0 =

2400

sec

onds

per

hou

r

T(70,t) - b0(70)t'

N(70,t) - q0(70)t'

1 2 3 4 75 6

1863

9206

7:14

:00

2341

3368

2509

4663

2595 28

81

1403

1017

2

8255

8958

6480

9146

8010

6772

8

7:33

:00

8:39

:00

8:49

:00

8:50

:00

8:57

:00

9:01

:00

7:51

:30

8:16

:30

9 10 11

3578

2705

3199

8880

9367

8904

3271

8629

SEGMENT #

QUEUENO QUEUE

7:41

:30

8130

9762

QU

Culver Dr.

University Dr.

Sand Canyon Ave.

Hwy. 133

Irvine Center Dr.

Travel Direction

Station140

130120

110100

9080

70

60

50

40

30

20

10

Station 70 – Loops 1-4 Oblique N and T

Time, t

Culver Dr.

University Dr.

Sand Canyon Ave.

Hwy. 133

Irvine Center Dr.

Travel Direction

0.60

1.60

2.60

3.60

4.60

5.60

7:00 7:30 8:00 8:30 9:00

Po

st m

ile

Station140

130120

110100

9080

70

60

50

40

30

20

10

-47000

-46500

-46000

-45500

-45000

-44500

-440007:

00

8:00

9:00

Time, t

N(6

0,t)

- q0t

', q

0 =

8500

vph

-11800

-11600

-11400

-11200

-11000

-10800

-10600

-10400

T(60

,t) -

b0t

', b

0 =

2000

sec

onds

per

hou

r

T(60,t) - b0(60)t'

N(60,t) - q0(60)t'15

1085

20

1 2 4 5 6 7 8

2010 25

82

3094

2438 16

31

1085

9525 95

60

7809

8379

7649

6103

7:14

:00

7:31

:30

7:34

:30

8:22

:00

8:39

:30

9:01

:00

2838

7906

8289

7511

2240

3172

9 10

7:54

:00

8:01

:00

3

7:22

:00

9208

1962

SEGMENT #

QUEUENO QUEUE

QU

Culver Dr.

University Dr.

Sand Canyon Ave.

Hwy. 133

Irvine Center Dr.

Travel Direction

Station140

130120

110100

9080

70

60

50

40

30

20

10

Station 60 – Loops 1-4, Oblique N and T

Time, t

Culver Dr.

University Dr.

Sand Canyon Ave.

Hwy. 133

Irvine Center Dr.

Travel Direction

0.60

1.60

2.60

3.60

4.60

5.60

7:00 7:30 8:00 8:30 9:00

Po

st m

ile

Station140

130120

110100

9080

70

60

50

40

30

20

10

Time, t

Culver Dr.

University Dr.

Sand Canyon Ave.

Hwy. 133

Irvine Center Dr.

Travel Direction

0.60

1.60

2.60

3.60

4.60

5.60

7:00 7:30 8:00 8:30 9:00

Po

st m

ile

Queue 1

Queue 2

Queue 4

Queue 5

Queue 7

Queue 3

Queue 6

Queue 9

Queue 10

Queue 8

Station140

130120

110100

9080

70

60

50

40

30

20

10

Queue - ActivationQueue - Deactivation

LEGEND

Results

Conclusions

• Ten Queues Formed at Five Locations• Flow Reduction of 3-15%• No Queue in HOV Lanes• Bottlenecks Typically Activated Near Ramps• No Speed Threshold Needed

Future Research

• Study site on different days• Manual replication of procedure• Develop semi-automated method

Acknowledgements• Prof. Pravin Varaiya and Prof. Alexander

Skabardonis, U.C. Berkeley• Dr. Karl Petty, Berkeley Transportation Systems• Pherak Hay, Vu Mai, and Roger Lindgren

Station 50, Occupancy

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

12:00 AM 2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00 PM 2:00 PM 4:00 PM 6:00 PM 8:00 PM 10:00 PM 12:00 AM

Time

Occ

up

ancy

Station 40, Occupancy

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

12:00 AM 2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00 PM 2:00 PM 4:00 PM 6:00 PM 8:00 PM 10:00 PM 12:00 AM

Time

Occ

up

ancy

-53500

-53000

-52500

-52000

-51500

-51000

-50500

7:00

8:00

9:00

Time, t

N(7

0,t)

- q

0t',

q0

= 9

500

vph

-14000

-13800

-13600

-13400

-13200

-13000

-12800

-12600

T(7

0,t)

- b

0t',

b0

= 2

400

seco

nd

s p

er h

ou

r

T(70,t) - b0(70)t'

N(70,t) - q0(70)t'

1 2 3 4 75 6

1863

9206

7:14

:00

2341

3368

2509

4663

2595 28

81

1403

1017

2

8255

8958

6480

9146

8010

6772

8

7:33

:00

8:39

:00

8:49

:00

8:50

:00

8:57

:00

9:01

:00

7:51

:30

8:16

:30

9 10 11

3578

2705

3199

8880

9367

8904

3271

8629

SEGMENT #

QUEUENO QUEUE

7:41

:30

8130

9762

QU

Station 70 – Loops 1-4 Oblique N and T

-47000

-46500

-46000

-45500

-45000

-44500

-44000

7:00

8:00

9:00

Time, t

N(6

0,t)

- q

0t',

q0

= 8

500

vph

-11800

-11600

-11400

-11200

-11000

-10800

-10600

-10400

T(6

0,t)

- b

0t',

b0

= 2

000

seco

nd

s p

er h

ou

r

T(60,t) - b0(60)t'

N(60,t) - q0(60)t'

1510

8520

1 2 4 5 6 7 8

2010 25

82

3094

2438 16

31

1085

9525 95

60

7809

8379

7649

6103

7:14

:00

7:31

:30

7:34

:30

8:22

:00

8:39

:30

9:01

:00

2838

7906

8289

7511

2240

3172

9 10

7:54

:00

8:01

:00

3

7:22

:00

9208

1962

SEGMENT #

QUEUENO QUEUE

QU

Station 60 – Loops 1-4, Oblique N and T