About
Project elements
Build a new climbing lane on I-5 south from the Hood Avenue on-ramp to the Multnomah Boulevard off-ramp in Portland.
Background
The I-5 south climbing lane concept has been listed in the Metro Regional Transportation Plan since 2014 (RTP project #11984).
The location was identified as a bottleneck in ODOT’s 2013 Corridor Bottleneck Operations Study and the improvement concept was studied as part of the 2019 Corridor Bottleneck Operations Study 2, which indicated operational and safety benefits from providing the climbing lane for slower moving vehicles. The 2023 Oregon Freight Plan identifies this portion of I-5 as a freight highway delay area and a Tier 1 priority bottleneck area.
Needs
I-5 southbound encounters a significant incline in Portland as it leaves the South Waterfront area and approaches the Terwilliger Curves and Burlingame neighborhood in southwest Portland. I-5 has high volumes of both cars and trucks. Slower vehicles, including heavy trucks, contribute to greater speed differential between the three lanes in this segment of I-5.
In addition, a congestion bottleneck occurs at the north end of the study area during the afternoon peak period. In this area, the Hood Avenue on-ramp enters I-5 just ¼ mile south of where I-5 joins traffic from I-405 and downtown Portland. Optimal interchange spacing for urban freeways is no less than one mile apart. Crashes occur with greater frequency near the Hood Avenue on-ramp, the Terwilliger curves and the Terwilliger Boulevard off-ramp.
Analysis
Staff compared the operational performance of four concept options and a no-build option using Highway Capacity Manual software (HCS) with 2023 as the analysis year. HCS analysis shows the performance of each segment of I-5 southbound in the study area, including the Hood Avenue, Terwilliger Boulevard and Multnomah Boulevard on- and off-ramp merge areas. For each option studied, performance is expected to improve within the area of the proposed climbing lane.
Location
I-5
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I-5 south from the Hood Ave on-ramp to the Multnomah Boulevard off-ramp.
Cost and Funding
TBD
Benefits
- Up to 43% reduction in total crashes and up to 46% reduction in fatal and injury crashes with the implementation of a climbing lane.
- Enables slower moving vehicles and trucks to climb the steep grade and curves towards the Terwilliger Boulevard off-ramp without mixing with the rest of I-5 traffic.
- 10% travel time savings in the afternoon peak hour.
- Implements improvements consistent with the Oregon Freight Plan and Metro Freight Strategy.
Additional Information
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