WSDOT presentation to Nisqually River Council

1. Interstate 5: Tumwater to Mounts Road
Mid- to Long-Term Strategies
Nisqually River Council
December 20th, 2019
Dennis Engel Matthew Pahs
Olympic Region Multimodal Planning Manager Principal Senior Planner

2. 2
Funding legislation
$550,000 in state and local funds to identify potential improvements
between exit 116 and exit 99 of Interstate 5. The study should
• further develop mid- and long-term strategies,
• identify potential US101/I-5 interchange improvements,
• a strategic plan for the Nisqually River bridges,
• regional congestion relief options, and
• ecosystem benefits to the Nisqually River estuary for salmon
productivity and flood control
-Engrossed Senate Substitute Bill 6106 Session Law, 2018 Regular Session

3. 3
Study area limits
• Southern end point:
Exit 99 – SR 121/93rd Ave
• Northern end point:
Exit 116 – Mounts Road
• Included I-5 between
Mounts Road and Main
Gate at JBLM in travel time
measures
• Included all of Thurston
County and parts of Pierce
County for regional
measures such as VMT

4. 4
Study purpose and goals
I-5 and major connecting routes between Tumwater and Mounts Road affect our region’s
economic vitality, accessibility and mobility, defense operations, and the environment. This
segment of I-5 is experiencing increasing congestion. Performance-based strategies are needed
to satisfy the following goals (not listed in order of priority):
• Improve travel times and reliability
• Increase the ability to safely, efficiently, and equitably move all people (multimodal) and
goods, and manage corridor capacity as an asset
• Improve accessibility to industrial areas, commercial areas, and job sites
• Protect and enhance the environment including reducing the transportation and
estuarine habitat constraints related to the Nisqually River Bridges and the river’s
delta.
• Improve network redundancy and resiliency

5. 5
Modeling Scenarios
Scenarios Examples of modeled strategies
Operations • Extra lane at Nisqually Interchange
• Roundabouts on SR 507 near Yelm
Land Use • Sustainable Thurston – growth concentrated in urban centers and
corridors
Travel demand management • Increased parking rates in urban core
• Increased telework and schedule shifts
Transit • Full implementation of Intercity Transit’s long-range strategic plan
Hard shoulder running • Peak period general purpose shoulder use on I-5 between Sleater-
Kinney and Henderson
HOV conversion • Convert one existing general purpose lane to HOV from US 101 through
38th in Tacoma
Interchange improvements • Braided ramp at US 101 and I-5
• Martin Way interchange reconfiguration
Capacity expansion – HOV • Add 4th lane through study area as an HOV lane
Capacity Expansion – General purpose • Add 4th lane through study area as a general purpose lane

6. 6
Performance measures
Study goal areas Performance measures
Travel times and reliability  Corridor travel times
 Maximum Throughput Travel Time Index (all traffic, HOV)
Multimodal efficiency & equity  Corridor person throughput (all traffic, HOV)
 County-wide mode split
 County-wide vehicle miles traveled
 Traffic Balance on I-5 (percent through traffic)
 Access for Environmental Justice populations (poverty,
minority, disability, no vehicle access)
Accessibility  County-wide access (SOV, HOV, & Transit) to
o Jobs
o Commercial services
 Travel times on selected freight access routes
Environment  Greenhouse gas emissions
Resiliency  Qualitative comparison “Improves availability and/or capacity of
alternate routes”
 Travel times on alternate routes through study area

7. 7
Modeling
Used a practical solutions approach
• Modeled lower cost strategies first such as
operations and TDM
Included all improvements from
previous scenarios
• Exception – Widening scenarios did not include
Hard Shoulder Running
• Did this to see cumulative effect of lower cost
strategies

8. 8
Modeling – 2040 baseline scenario Mounts Road

9. 9
Modeling – 2040 baseline scenario – US 101/Plum

10. 10
Draft strategy recommendations
Scenario Priority Draft recommendations
Land Use 1 Recommended short-term/mid-term/ongoing
Transit 2 Recommended short-term/mid-term/ongoing
Travel Demand Management 3 Recommended short-term/mid-term/ongoing
Operations 4 Recommended short- and mid-term
Hard Shoulder Running 5 Recommended mid-term
Interchange Improvements 6 Recommended mid-term/long-term
HOV Conversion 7 Recommended mid-term
Capacity Expansion I-5 - HOV1,2 8 Consider long-term
Capacity Expansion I-5 All GP2 - Not recommended
Short-term (0-4 years), mid-term (5-9 years), long-term (10-20 years)
Unless otherwise noted, scenarios included all improvements from previous scenarios
1 The benefits of HOV lanes are accounted for in the HOV conversion scenario, the Capacity Expansion I-5 – Add GP Lane, Retain HOV Lane adds general purpose
capacity not an HOV lane
2 Does not include Hard Shoulder Running, instead has permanent auxiliary lanes

11. 11
Hydrologic Study
WSDOT and the Nisqually Indian Tribe fully
funded this study ($150,000 each)
Nisqually Tribe working with USGS
• Updating & validating modeling
• Analyzing historic water levels, storm surge, wave heights,
and extreme flood events
Draft results expected in November

12. 12
Next steps
Next steps for this study
• Public engagement in late November/early December
• Report review in December
Planning Environmental Linkages Study
• WSDOT has advertised a Request for Qualifications
• Expect consultant selection in January
• PEL study will further refine solutions in cooperation with resource agencies
Project webpage: https://www.wsdot.wa.gov/planning/studies/i5/tumwater-mounts-road/home