columbia river crossing bottleneck simulation (1)

Columbia River Crossing Bottleneck SimulationBRYAN BLANC

ALI RAZMPA

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PurposeUse a simulation tool to analyze real-world data

Compare alternative designs for transportation facilities and their effects on transportation operations

2Columbia River Crossing Bottleneck Simulation

ObjectivesCompare the existing Columbia River Interstate Bridge facility with the proposed design during PM peak usage conditions on the Northbound Side.

Propose minor improvements that can be made to the bridge now, until full construction (eventually) takes place on a new bridge


Study BoundariesAnalyzing average Friday conditions during Summer (June-August) of 2013 between 12 PM and 10 PM.


Segment Examined (Northbound only)

Ore

gon

Was

hin

gto

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Image from Google Earth

Data SourcesLoop detector data for I-5 freeway segment and on ramp volumes taken from PORTAL

Off ramp flows taken from Columbia River Crossing Traffic Technical Report1

Heavy vehicle assumptions from Columbia River Crossing technical report on existing freight conditions2

1: http://www.columbiarivercrossing.org/FileLibrary/TechnicalReports/Traffic_TechnicalReport.pdf2:http://www.columbiarivercrossing.org/FileLibrary/TechnicalReports/TruckFreightExistingConditions.pdf


Simulation ToolVISSIM 6.0


Data Input :Volume (vph) Relative Flow (%)

Speed limits:Interstate 5 = 55 mphN Denver Ave to I-5 (on-ramp) = 45mphMarine Dr. W to I-5 (on-ramp)= 25mphN Hayden Island Dr to I-5 (on-ramp)= 25mphColumbia river I-5 Bridge =50 mph

5000 ft before the diverge & 3000 ft before the lane dropLane change:

Driving behavior:

Vehicle Compositions:Cars= 90%Trucks= 8%Buses= 2%

Signal Controllers:

Two Ramp Metering on on-ramps

Design AlternativesExisting6-lane freeway bridge, problematic accesses are primary cause of bottleneck

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Image from Google Earth

Time Avg Speed Avg Delay

2:00 PM - 3:00 PM 18 mph 188 Sec

Proposed12-lane freeway bridge, improved accesses

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2:00 PM - 3:00 PM 41 mph 8.5 Sec

Our Test Alternative

Remove on-ramp for Hayden Island on Northbound side. Add one lane leading up to Columbia River Interstate Bridge (using existing shoulder)

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2:00 PM - 3:00 PM 26 mph 102 Sec

Average Speed

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11:00 AM 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PM 7:00 PM 8:00 PM 9:00 PM 10:00 PM

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Existing Proposed Alternative

Columbia River Crossing Bottleneck Simulation

Total Travel Time on Segment

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Total Delay on Segment

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Difference in Performance

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+60%

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-80%

+44%

-16%

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-100%

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Average Speed in Segment (mph) Total Travel Time in Segment (VHT) Total Delay in Segment (hours)

Proposed Alternative


DiscussionEstimated Costs:Proposed: $3.1-3.5 BillionOur Test Alternative:<$100 Million

Could removing accesses be a temporary solution to mitigating congestion? Is it politically feasible? (Beyond the scope of this

project)

Other Possibilities:Demand reductionLimits on freight travel during peak hours


Issues and LimitationsData validityIssues with speeds reported in PORTAL as compared to

those generated by simulation (using volumes from PORTAL). Which is more reliable measure of speed?

Simplified test scenarioSimplifying assumptions were made that may not be

valid under realistic conditions

Study boundariesSmall portion of corridor was analyzed



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Average Speed

Simulated Portal

Project OutcomesGained experience in utilizing real world data with a simulation tool

Simulation allowed us to gain greater understanding of bottleneck conditions on Columbia River bridge


Questions?

Thank you for your attention!20

Source:http://www.macalester.edu/academics/environmentalstudies/students/projects/citizenscience2010/columbiariverbridge/crcfuture.html

columbia river crossing bottleneck simulation (1)

Engineering