Transportation Engineering

Reducing rear-end crashes by improving visibility of intersection

Most crashes at this intersection are rear-end collisions. Includes installing a radar detection system to detect vehicles as they approach the Knights Bridge Road/Arndt Road intersection. The detection prevents the signal from changing to another direction prematurely and placing drivers in a dilemma of deciding to go through the intersection or not, causing longer wait times. Also adding signal ahead signs and pavement markings to alert drivers of changing conditions. 

Why

To provide a safer roadway for all users by increasing visibility of intersection.

Schedule

• Design: Dec. 2023 to June 2024
• Construction: Sept. 2024 to June 2025

Traffic impact

Traffic impacts will be minor during installation.

Current activities

Project planning. 

Funding

• Project estimate $325,000.
• Funding is provided from HB2017 state gas taxes.

The 12’ metal culvert carrying Henry Creek under Arlie Mitchell Road in the Rhododendron area does not easily allow fish and wildlife to pass upstream and will be replaced with a modular bridge. This project is the result of collaboration among several groups, including Clackamas County, ODFW, the City of Portland, the Forest Service and the Freshwater Trust. The Freshwater Trust will lead the project. Clackamas County will provide survey, right-of-way acquisitions, plan review, public outreach, and construction inspection services. 

Why

To minimize potential impacts to the roadway due to flooding and to provide access for fish and other aquatic organisms to reach upstream cold-water habitat.  

Schedule

• Design: April 2023 – June 2023
• Right of way: Feb. 2024 – June 2024
• Construction: July 2024 – December 2025

Traffic impact

• A road closure will be needed during construction for up to 2 months; tentatively planned from 7 a.m. to 7 p.m., Aug. 19 - Dec. 13, 2024.
• Detours: Access to properties south of the culvert crossing on Arlie Mitchell Road, will use Arlie Mitchell Road. Access to properties north of the culvert crossing, and to Henry Creek Road, will use Henry Creek Road.  
• Project is expected to take up to 5 months to construct.
• Site work planned to take place during the prescribed in-water work period of July 15 to August 31

Current activities

• Preparing for construction

Funding

• Project estimate $1.4 million. 
• Funding is provided from grants including: Oregon Department of Fish and Wildlife, the City of Portland, the Oregon Watershed Enhancement Board, Forest Service, Freshwater Trust, and a contribution from county road funds. 

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Increasing stormwater capacity to reduce flooding and improve maintenance access

Flooding on El Camino Way, El Centro Way, El Centro Ct and La Mesa Way roads in the Oak Grove area occurs periodically. To reduce the frequency of flooding and to provide stormwater infrastructure with capacity for a 10-year storm event, we will replace the existing stormwater pipes. Currently, most of the stormwater pipes exist on private property and most of the pipes will be moved to existing roads within the public right of way. Constructing the storm pipes within the right of way will be easier to maintain.

Why

To decrease the frequency of flooding, improve maintenance access, and to comply with Oak Lodge Water District and Clackamas County standards requiring stormwater collection systems to provide for a 10-year storm event for this size of drainage basin.

Schedule

• Design: Feb. 2023 to April 2024
• Right of way: Dec. 2023 to April 2024
• Construction: Spring 2025 to Fall 2025

Traffic impact

• Expect shoulder and lane closures and detours with delays up to 20 minutes during construction.

Current activities

• Project planning and solicitation of design services.

Funding

• Project estimate $1.4 million 
• Funding is provided from American Rescue Plan Act (ARPA) funds.

Increasing stormwater capacity to reduce flooding and improve fish habitat and waterway access

Kellogg Creek flows through an undersized culvert causing the creek to back up at SE Thiessen Road and flood the road and properties upstream. We will replace the culvert with a larger culvert to allow water to move naturally for lower stream flows in the summer and higher stream flows from large storm events in the winter. Vegetation will be planted at both ends of the culvert to restore stream habitat.

Why

To decrease the frequency of flooding on the roadway and water backed up on adjacent properties upstream, and improve the habitat and ability for fish to pass through the culvert carrying Kellogg Creek.

Schedule

• Design: April 2023 to Dec. 2024
• Right of way: April 2024 to Winter 2024/2025
• Construction: Spring 2025 to Winter 2025/2026

Traffic impact

• Expect shoulder and lane closures and detours with delays up to 20 minutes during construction.

Current activities

• Project planning and solicitation of design services.

Funding

• Project estimate $1.5 million paid for with American Rescue Plan Act (ARPA) funds.