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Highway Design

Rebuilt interchanges will improve safety and efficient movement of vehicles

Up to 75 percent of vehicles traveling across the Interstate Bridge during peak hours use one or more of the project area interchanges. Short distances between interchanges slow traffic as people get on and off, which can contribute to accidents. Highway improvements will keep traffic moving through the area north and south of the I-5 bridge which will reduce collisions.

Improvements will be made at the following interchanges, as described in the Final Environmental Impact Statement:

• Marine Drive
• Hayden Island/Jantzen Beach
• SR 14/City Center
• Mill Plain
• Fourth Plain
• SR 500

Auxiliary lanes will be added between closely-spaced interchanges. These lanes help to improve safety and reduce congestion by providing space for cars and trucks to reach highway speeds before merging or to slow down to exit. The highway will be widened to include up to two auxiliary lanes in each direction.

I-5 will transition back to the current number of lanes at the northern and southern project area boundaries, Highway 99 in Vancouver and Delta Park in Portland.  More info: Bridge and Highway Lanes

Marine Drive

The Marine Drive interchange currently has a partial “clover leaf” form with long looping ramps. Planned improvements will help reduce congestion and improve safety for trucks and other motorists entering and exiting I-5. The proposed configuration is a Single-Point Urban Interchange (SPUI) that allows vehicles to move freely with fewer traffic signal phases.

Highlights include:

• A higher-speed right turn from eastbound Marine Drive to I-5 southbound.
• A higher-speed right turn from Martin Luther King Jr. Boulevard to I-5 northbound.
  
• A new local bridge between Hayden Island and Marine Drive separated from I-5.
• A new elevated ramp for motorists to travel from Marine Drive eastbound to I-5 northbound without stopping. This element would be constructed as a future phase.

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Hayden Island

The Hayden Island interchange reconfiguration will help reduce crashes and improve merging speeds. The design provides direct I-5 access, as well as local access via a non-highway bridge over North Portland Harbor that connects to North Portland. More info: Hayden Island Interchange

Highlights include:

• Longer ramps for entering and exiting I-5.
• Access to/from Hayden Island without having to enter the highway.
• Improved access across the island via an extended Tomahawk Island Drive under the highway. This element could be constructed in a future phase.

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SR 14/City Center

Connections between I-5 and SR 14 will be rebuilt. Highway access points to and from downtown Vancouver will be relocated.

Highlights include:

• Extending Main Street from 5th Street south to Columbia Way.
• Shifting access to and from I-5 south to C Street from the current access point at Washington Street.
• Connecting SR14 to Washington Street and Columbia Street at 4th Street.
• Lengthening the distance between the exit ramps from I-5 northbound at SR 14 and City Center.
• Adding a parallel roadway (collector-distributor) between the SR 14 interchange and the Mill Plain interchange to improve merging.

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Mill Plain Boulevard

The Mill Plain Boulevard interchange currently has a “diamond” configuration that requires two traffic signals to move vehicles through the interchange. It will be reconfigured into a Tight Diamond Urban Interchange (TDUI) that uses a pair of efficient intersections that operate as one intersection to reduce delays for traffic entering or exiting I-5.

Highlights include:

• Adding a second right turn lane from I-5 south to downtown Vancouver.
• Adding a parallel roadway (collector-distributor) in both highway directions between Mill Plain Blvd. and SR 14 to connect the interchanges and improve merge operations.

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Fourth Plain Boulevard

Improvements to this interchange will better accommodate freight traffic and provide access to the new park and ride facility located near Clark College and the Central Park neighborhood.

Highlights include:

• Widening highway access intersections to better accommodate large trucks.
• Adding a southbound road to Fourth Plain Blvd. providing access to the new park and ride facility.
• Separating southbound I-5 access to Fourth Plain Blvd. from SR 500 to avoid conflict with merging traffic. Direct connections between westbound SR 500 and Fourth Plain Blvd. will be eliminated. Travelers will instead use 39th Street or Mill Plain Blvd. to access Fourth Plain Blvd.

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SR 500

The CRC project will make improvements to provide safer merging from SR 500 to I-5 south. Improvements will be made in a future construction phase to create a direct connection from SR 500 to I-5 northbound and I-5 southbound to SR 500.

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Community input has shaped interchange design

Public comments and input received from advisory groups has helped inform staff and elected officials in their deliberations related to CRC project design and development.

The Portland Working Group and attendees at three public meetings provided feedback on concepts considered for the new Hayden Island interchange. This input helped select a design that could address many of the concerns expressed with previously studied designs. More on Hayden Island interchange design.

The Marine Drive Stakeholder Group, a diverse group of Oregon community members, agency staff and business leaders recommended the current proposed alignment for the Marine Drive interchange that was advanced for additional design work and environmental impact analysis.