Using Archived Data to Measure Operational Benefits of a System-wide Adaptive Ramp Metering (SWARM) ...
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Using Archived Data to Measure Operational Benefits of a System-wide Adaptive Ramp Metering (SWARM) System. April 18, 2006 Dr. Robert Bertini Dr. Sue Ahn Dr. Chris Monsere. Presentation Outline. 1. Literature Review 2. Corridor Selection for Pilot Study 3. Data Collection Plan.

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April 18, 2006 Dr. Robert Bertini Dr. Sue Ahn Dr. Chris Monsere

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April 18 2006 dr robert bertini dr sue ahn dr chris monsere

Using Archived Data to Measure Operational Benefits of a System-wide Adaptive Ramp Metering (SWARM) System

  • April 18, 2006

  • Dr. Robert Bertini

  • Dr. Sue Ahn

  • Dr. Chris Monsere


Presentation outline

Presentation Outline

1. Literature Review

2. Corridor Selection for Pilot Study

3. Data Collection Plan


April 18 2006 dr robert bertini dr sue ahn dr chris monsere

1. Literature Review


System wide adaptive ramp metering

System-wide Adaptive Ramp Metering

  • Competitive, Traffic-Responsive Algorithm

  • SWARM 1: Global control

  • Forecasts density at a bottleneck and determines the required volume reduction for upstream ramps

  • Determines the individual metering rates based on the overall volume reduction required

  • SWARM 2: Local control

  • Determines the metering rate independently for each on-ramp based on the local condition

  •  Actual rates: more restrictive of the two rates


System wide adaptive ramp metering1

System-wide Adaptive Ramp Metering

  • Capabilities

  • Potential to detect congestion in advance with high accuracy

  • Robustness: Built-in failure management (data clean-up)

  • Potential Problems

  • Potential ill-performance when forecasts are not accurate

  •  Good prediction models are key


Swarm field testing

SWARM Field Testing

  • Orange County, CA (MacCarley et al., 2000)

  • The field-testing could not be conducted because

  • the SWARM algorithm did not operate correctly when tested for six weeks.

  • Caltrans did not receive proper training nor documentation to fully understand the SWARM system.

  •  Testing via Paramics (Zhang et al., 2001)

    •  SWARM was sensitive to the accuracy of the predictions


Swarm field testing1

SWARM Field Testing

  • LA and Ventura Counties, CA (Pham et al., 2002)

  • 1,200 ramp-meters in the region

  • Existing ramp-metering: pre-timed, local traffic-responsive

  • Tested on 20 controlled on-ramps on a freeway corridor (Route 210 W) during morning peaks (between September 2001 and January 2002)

  • A couple of days for each of the following strategies

    • SWARM 1 only: testing the global control only

    • SWARM 2b only: testing the local control only

    • SWARM 1/2b combined: testing the global and local controls


Swarm field testing2

SWARM Field Testing

  • LA and Ventura Counties, CA (Pham et al., 2002)

  • Results: SWARM 1/2b generated most benefits

  • Mainline Freeway:

    • Speed increased by 11%

    • Travel time decreased by 14%

    • Occupancy decreased by 13%

    • Delay decreased by 17%

    • Volume increased by 1%


Swarm field testing3

SWARM Field Testing

  • LA and Ventura Counties, CA (Pham et al., 2002)

  • On-ramps (at the nine busiest locations):

    • Volume decreased by 9%

    • Queue lengths increased by 41%

  • Limitations:

    • Small sample size (only a couple of days of testing)

    • No analysis on spatial equity

    • No analysis on traffic diversion to alternative routes

    • No analysis on change in the distribution of inflows


Swarm field testing4

SWARM Field Testing

  • Some Future Plans

  • LA and Ventura Counties

    • Ramp meter development plan in 2005

    • More testing of SWARM

  • Fresno County (District 6)

    • Proposal for a pilot study

  • Orange County (District 12)

    • No updated status yet


Other traffic responsive algorithm

Other Traffic-Responsive Algorithm


Field testing zone algorithm

Field Testing: ZONE Algorithm

  • Shut-off Experiment in Minneapolis, MN (Fall of 2000)

  •  The meters were shut off for eight weeks.

  • Conditions on mainline freeway

  • Traffic diversion to alternative routes

  • Change in travel behavior

  • On-ramp queue lengths

  • Cambridge Systematics, 2001

  • Kwon et al., 2001

  • Hourdakis and Michaelopoulos, 2002

  • Levinson and Zhang, 2002


Field testing zone algorithm1

Field Testing: ZONE Algorithm

  • Shut-off Experiment in Minneapolis, MN (Fall of 2000)

  •  The meters were shut off for eight weeks.

  • Results: (Cambridge Systematics 2001, etc.)

    • During the peak periods, freeway mainline throughput declined by an average of 14% with the ramp meters off.

    • Travel time increased by more than 25,000 (annualized) hours.

    • Crash frequency increased by 26% while the meters were off.

    • Ramp-metering resulted in more delay on on-ramps but generated system-wide delay.


Field testing zone algorithm2

Field Testing: ZONE Algorithm

  • Shut-off Experiment in Minneapolis, MN (Fall of 2000)

  •  The meters were shut off for eight weeks.

  • Levinson and Zhang (2002)

  • Evaluated the system with seven measures: (mobility, accessibility, equity, consumers’ surplus, travel time variation, productivity, and travel demand responses)

  • Favorable results for ramp-metering

  • Equity analysis: worse off with ramp-metering

    •  travel time for short trips increased while the travel time for longer trips decreased.


Other field testing

Other Field Testing

  • Helper Algorithm: Denver, CO

  • Bottleneck Algorithm: Seattle, WA

  • Fuzzy Logic Algorithm: Seattle, WA / Zoetermeer, Netherlands

  •  Similar Results (Favorable to ramp-metering)


April 18 2006 dr robert bertini dr sue ahn dr chris monsere

2. Corridor Selection


Freeway network in portland

Freeway Network in Portland

source: www.tripcheck.com


Swarm implementation schedule

SWARM Implementation Schedule


Corridor selection criteria

Corridor Selection Criteria

  • 1)Level of congestion

    • Duration and spatial extent of congestion should be reasonably large (i.e., no localized queue).

    • Assessment of the SWARM performance while SWARM 1 mode (global control) interacts with SWARM 2 modes (local control) at multiple on-ramp locations.

  • 2)Spatial extent of queues: Isolated queues within a corridor

    • The head and tail of a queue should reside within a corridor.

    • This ensures a system-wide evaluation of the SWARM system within corridor without having to evaluate other intersecting freeways simultaneously.


Corridor selection criteria1

Corridor Selection Criteria

  • 3)Coverage of Loop detectors

    • Good coverage over the entire corridor

    • Reasonable spacing between loop detectors (≈1 mile)

  • 4)Data quality

    • Corridors for the pilot study will be selected based on their history of data quality

    • Rare communication failure

    • Large proportion of “good” readings

    • = (No activity + OK + Suspects) / all readings


Corridor selection criteria2

Corridor Selection Criteria

  • 5)Feasibility of analyzing traffic diversion

    • This requires identifying possible alternative routes and obtaining necessary data to measure traffic diversion.

    • Feasibility of collecting data on all alternative routes should be taken into consideration in selecting a study corridor.

  • 6)Stability of the SWARM system implemented

    • All ramp meters should be working properly

    • No bug in the implemented algorithm: actual metering rates = theoretical rates


Corridor selection criteria3

Corridor Selection Criteria

  • 7)Construction schedule

    • Exclude corridors that are scheduled for construction.

    • Excluded corridors will be re-considered for the regional-level evaluations.

  • 8)Presence of HOV lane or transit service

    • Changes in demand for a HOV lane or transit service on freeways or on alternative routes.

    •  It is highly unlikely that people change their travel behavior in the short run.


Corridors not recommended

Corridors NOT recommended

  • US-26 (East and Westbound)

    • Under major construction to expand a travel lane.

    • May be considered for the regional-level evaluation.

  • I-84 (East and Westbound)

    • EB: Only five loop detector stations, spanning less than 4 miles.

    • WB: Four loop detector stations, spanning 3 miles, and the 5th one is located 10 miles upstream.

    • Queues are not isolated within the section.

    • Only two or three on-ramps are metered on this corridor.


Speed contour i 84 eb

Speed Contour: I-84 EB

60th St.

Morrison Bridge


Corridors not recommended1

Corridors NOT recommended

  • I-405 (Northbound)

  • Relatively short (≈ 3.5 miles).

  • Only two loop detector stations, covering less than 1 mile.

  • Queues are not isolated.

  • I-405 (Southbound)

  • Relatively short (≈ 3.5 miles).

  • Lightly congested during the peaks with a small queue (≈ 1.5 mile).

  • The head of a queue is located at the most downstream end.


Speed contour i 405 sb

Speed Contour: I-405 SB

Front Ave.

Count Station


Corridors not recommended2

Corridors NOT recommended

  • I-205 Southbound

    • This corridor is lightly congested during the peaks. (speed > 40 mph throughout the whole corridor)

  • OR 217 Northbound

    • Lightly congested during the peaks (speed > 45 mph).

    • Queue are not isolated:A queue forms near the junction with 99W and spills-over to I-5.


Speed contour i 205 sb

Speed Contour: I-205 SB

Airport Way

Stafford


Speed contour or 217 nb

Speed Contour: OR 217 NB

72nd

99W

Walker


Corridors not recommended3

Corridors NOT recommended

  • I-5 Upper Northbound

    • A major bottleneck at the South end of the Interstate Bridge?  This could not be verified since no loop detector data are received downstream of the bridge (Vancouver, WA).

    • History of communication failure

    • HOV lane


Speed contour i 5 upper nb

Speed Contour: I-5 Upper NB

Jantzen Beach

upper

Willsonville


Corridors not recommended4

Corridors NOT recommended

  • I-5 Upper Southbound

    • Queues are not isolated: a queue forms near Columbia Blvd. and spills-over to Vancouver, WA.

  • I-5 Lower Southbound

    • AM and PM peaks: usually a small queue from near the Wheeler Ave. on-ramp (≈2 – 3 miles)

    • AM peak: often overrides the upstream bottleneck near Columbia Blvd. and the resulting queue propagates to WA

    • Large spacing between Wheeler and Hood Ave. (> 2 miles)


Speed contour i 5 sb

Speed Contour: I-5 SB

Jantzen Beach

Columbia

upper

lower

Wheeler

Hood

Nyberg


Swarm implementation schedule1

SWARM Implementation Schedule


Candidate corridors or 217 sb

Candidate Corridors: OR 217 SB

source: www.tripcheck.com


Candidate corridors or 217 sb1

Candidate Corridors: OR 217 SB

72nd

Greenburg

Denney

Barnes


Candidate corridors or 217 sb2

Candidate Corridors: OR 217 SB

  • OR 217 Southbound

    • Good amount of congestion in the morning and evening

    • Few alternative routes

    • Good history of loop detector data quality (> 95%)

    • Good detector spacing (good coverage) (< 1 mile)

    • No transit service or HOV lane on the freeway

  • Questions/Issues:

    • Operation hours: 6 AM – 10 AM?

    • Isolated queue  ? (spill-over from I-5S?)

    • Transit service on alternative routes?  www.trimet.org

    • Any construction scheduled?


Candidate corridors i 5 lower nb

Candidate Corridors: I-5 Lower NB

source: www.tripcheck.com


Speed contour i 5 lower nb

Speed Contour: I-5 Lower NB

Jantzen Beach

Morrison

lower

Macadam

Willsonville


Candidate corridors i 5 lower nb1

Candidate Corridors: I-5 Lower NB

  • I-5 Lower Northbound

    • Good amount of congestion in the evening

    • Isolated queues

    • No HOV lane on the freeway

  • Questions

    • Operating hours: 6 – 10 AM, 1 – 7 PM?

    • Any construction scheduled?

    • Transit service on freeway: ridership data?

    • How about on alternative routes?  www.trimet.org


Candidate corridors

Candidate Corridors

  • I-5 Lower Northbound

  • Issues:

    • Several alternative routes

    • One segment with detector spacing > 2 miles (between Macadam Ave. and Bertha Ave.): any device?

    • Data quality (% good readings < 95%)

      • April 2006: Terwilliger Blvd NB (42%), Morrison BR (~90%), Broadway (74%), Alberta St. (68%)

      • March 2006: Pacific Hwy (23%), Broadway (82%), Alberta St. (53%)

      • February 2006: Pacific Hwy (0%), Broadway (88%), Alberta St. (75%)


Candidate corridors i 205 nb

Candidate Corridors: I-205 NB

source: www.tripcheck.com


Speed contour i 5 nb

Speed Contour: I-5 NB

Division

Powell

OR 43

Stafford


Candidate corridors1

Candidate Corridors

  • I-205 Northbound

    • Good amount of traffic in the morning and evening

    • Good data quality

    • Two recurrent bottlenecks (one near Division St. and the other near the junction with OR 43)

    • No HOV lane


Candidate corridors2

Candidate Corridors

  • I-205 Northbound

  • Questions/Issues:

    • Construction?

    • Transit service on freeway?

    • Isolated queue? (bottleneck at Powell or Division?)

    • An upstream queue is not usually isolated within this corridor (spill-over to I-5S)


April 18 2006 dr robert bertini dr sue ahn dr chris monsere

3. Data Collection Plan


Summary of data collection plan

Summary of Data Collection Plan


Summary of data collection plan1

Summary of Data Collection Plan


April 18 2006 dr robert bertini dr sue ahn dr chris monsere

4. Experimental Design


Candidate corridors or 217 sb3

Candidate Corridors: OR 217 SB

Alternative Routes


Candidate corridors or 217 sb4

Candidate Corridors: OR 217 SB

  • Alternative Routes

  • Cedar Hills – SW Hall Blvd.

  • SW Murray Blvd.


Candidate corridors or 217 sb5

Candidate Corridors: OR 217 SB

  • On-ramp volumes and queue storage length


April 18 2006 dr robert bertini dr sue ahn dr chris monsere

Candidate Corridors: OR 217 SB


Candidate corridors i 5 lower nb2

Candidate Corridors: I-5 Lower NB

Alternative Routes


Candidate corridors i 5 lower nb3

Candidate Corridors: I-5 Lower NB

Alternative Routes


Candidate corridors i 5 lower nb4

Candidate Corridors: I-5 Lower NB

  • Alternative Routes

  • SW Boones-Ferry Rd. – SW 72nd Ave. – 99W

  • Boones-Ferry Rd. – SW Terwilliger Blvd.

  • Macadam Ave. (OR 43)


Candidate corridors i 5 lower nb5

Candidate Corridors: I-5 Lower NB

  • On-ramp volumes and queue storage length


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