The planning process includes improvements along three segments of the SR37 corridor. Segment A extends from US 101 in Marin County for 3.4 miles and continues for 3.9 miles in Sonoma County to the SR 121 junction. Segment B includes a portion of SR37 just east of Sears Point, where it crosses the Napa/Sonoma marshlands from SR121 to Mare Island, with 2.3 miles in Sonoma County and 7 miles in Solano County. Segment C starts at Mare Island and extends for 4.4 miles to the SR37 termination at I-80 in Solano County.

Investing in Segment B congestion relief is designed to reduce travel times from 100 minutes to 24 minutes eastbound PM, and from 47 minutes to 23 minutes westbound in the AM. Given existing conditions based on 2017 data, user benefits from delay time saved is valued at $49M annually. With projected 2022 conditions, time saving benefits are estimated at $69M annually.

Smith outlined elements of an integrated transportation, ecology and sea level rise (SLR) adaptation program featuring several options for a resilient corridor including an examination of six known weak links along this route flooded during 2017 storms.

Two alternatives are being put forward by the Transportation Authority of Marin working on a funded Phase 1 study of sea level rise impacts on Segment A. Phase 2 will study levee protection alternatives as well as options for an elevated structure design, or causeway, that would be high enough to avoid sea level rise, as well as a hybrid design that would be partially elevated and return to the existing ground level roadbed in key areas. This work will be used for possible interim improvements as well as in the ultimate project segments (A+B) during the California Environmental Quality Act/National Environmental Policy Act review phase.

The program’s goals encompass improving resiliency of the transportation infrastructure to anticipate sea rise and flooding, improving traffic flow and peak travel times by relieving congestion and increasing person throughput, while enhancing the quality of life for residents and building a stronger local and regional economy for all.

It would also restore ecological and hydrologic flows to enhance productivity of wetlands and baylands, and provide accommodation for multimodal use (rail and transit alternatives) as well as facilitate public access to natural resources.

She said 30 years from today anticipated sea level rise will inundate SR37 unless steps are taken to prepare for this eventuality while also planning to protect this unique habitat and environment. There are nine special status species living in many acres of wetlands and baylands along a Pacific flyway that must be protected.

“The vision for SR37 corridor involves coordination on an approach among four North Bay counties that collectively share this route, including Marin, Sonoma, Napa and Solano Counties,” Smith said.

Even more critical is the fact that this route has become a key east-west link between more affordable housing in Solano and higher paying jobs closer to the coast.

The San Diego I-5 North Coast Corridor Program is a model for what could be developed in the North Bay. It involves spending $6B over 40 years derived from a ½ cent TransNet sales tax plus federal/state and local funds.

The anticipated cost of the SR37 program is $5B+ over 25 years. The plan includes four parts.

For the highway itself, it calls for adapting SR37 from I-80 to US101 for sea level rise; relieving congestion between Mare Island interchange and SR121, and including near-term operational improvements at SR121 and the Mare Island interchange. Interchange improvements would be made to Lakeville Highway, SR121, Mare Island, Atherton and at the fairgrounds. Also proposed is a grade separation with the SMART rail crossing at SR121.

Multimodal transportation options under consideration involve micro-transit service, a regional express bus service between Vallejo and Novation, and support strategies such as commuter parking, etc. The plan also anticipates future SMART passenger rail service between Novato and Suisun City in Solano County.

For the environment, the program includes advanced mitigation and enhancements, along with land acquisition for corridor restoration, targeted, smaller-scale, ecological enhancements and larger landscape-scale restoration.

Greater public access would be provided by a bicycle/pedestrian shared use path and improvement enabling easier access to open space, public viewing areas, and trail heads.

Smith said regional advance planning is focusing on upfront mitigation that will balance the needs of transportation and conservation to maximize benefits. Time would be saved by having a comprehensive framework to mitigate unavoidable biological resource impacts caused by infrastructure projects.

Money would also be saved and improve conservation outcomes would result by allowing for natural resources to be protected and restored as compensatory mitigation before infrastructure projects are constructed.

The Bay Area Regional Advance Mitigation Planning Program (RAMP) encourages agency communication. In 2015, the MTC and SCC launched an effort to scope and implement RAMP for the bay area by 2040. This plan could be expanded to include the SR37 Resilient Corridor Program, or a stand-alone SR 37 RAMP and Regional Conservation Investment Strategy (RCIS) program could evolve.

The California Department of Fish and Wildlife’s RCIS program supports RAMP by facilitating the development of mitigation credits contributing to regional conservation priorities while also providing advance mitigation for entities that require compensatory mitigation.

The CDFW’s regional conservation investment strategy is voluntary, non-regulatory regional planning process that can mean huge benefits to transportation project cost, implementation and conservation of marshlands.

It establishes biological goals, objectives, and describes conservation actions and habitat enhancements such as land acquisition and protection, habitat creation and restoration (including on public land), restoring creeks and rivers, wildlife crossings and the removal of fish barriers.

A number of targeted, smaller-scale ecological enhancement opportunities along the SR37 corridor could help mitigate near-term impacts while facilitating long-term ecological and hydrological goals. These include pilot living shoreline projects along Tolay Creek, Improved drainage of strip marsh south of SR37, removal of debris and regrading of upland on Mare Island north of SR37, improved public access at Sears Point and Tolay Creek, as well as improved tidal exchange upstream of the Tolay Creek Bridge.

Other ways to relieve congestion are being explored for Segment B, such as a managed lane option (similar to the movable barrier system on the Golden Gate Bridge) including a three-lane contra flow option, constructing a roundabout at the intersection of SR37 and SR121, and eastbound lane drop extension. On the west side of SR37, the Mare Island interchange westbound would be improved with lane drop extension and ramp metering. Shoulder running lanes are also being considered along with the widening of the Tolay Creek Bridge. Mitigation for bicycles during peak periods is another factor.

Delivery dates and costs of Segment B congestion relief were provided. For project approvals and environment documentation, the completion date is 2022 at a cost of $8M. For final design the completion date is the same with a cost of $12M. Construction completion is estimated in late 2025 at a cost of from $80M to $130M. The total cost of Segment B improvements is from $100M to $150M.

Five route design alternatives were studied for Segment B. The lowest travel times with no increase in daily Vehicle Miles Traveled are associated with having SR37 follow the current alignment using a hybrid solution combining an existing road/causeway plan (costing $2.48B) or a causeway from end to end costing $2.98B.

The plan calls for a means-based fare and toll system for SR37 users that would provide equitable access for all. Objectives for the MTC’s regional means-based transit fare pricing study include making transit more affordable, establishing a more consistent standard for fare discount policies, and finding solutions that are both financially viable and administratively feasible.

To achieve this, Smith said that the typical project delivery paradigm must be redesigned by forging atypical partnerships, by leveraging funding and finding ways to accelerate delivery. She said that a legislative approach should involve balancing highway, transit and environmental considerations, along with permitting, commitment and tolling parameters.

SB 468 and AB 1282 are viable funding mechanisms along with a plan that implements tolling on SR37 encompassing a Bay Area Toll Authority toll bridge and/or one-way or two-way tolling.

According to Smith, a phased implementation approach with concurrent project development can offer early community benefits by 2040. Benefits include SR37 congestion relief (SR121 to Mare Island) and ecological enhancements and bus transit. Long term, from 2040 to 2050 and beyond, the Resilient SR37 program can include SR37 corridor SLR adaption (I-80 to US 101); along with bike/pedestrian/public access and rail transit funded and delivered by SMART.

Smith presented several recommendations. She proposes establishing an integrated delivery team that would collaborate on the Segment B congestion relief project environmental and design; near-term State Highway Operation and Protection Program (SHOPP) projects; development of a Segment A project initiation document; an SR37 corridor State SLR adaption environmental plan; and SHOPP project components, including shoreline alternatives where possible.

She said legislation is needed to facilitate funding and that shoreline evaluation and implementation must be conducted and scheduled. Other priorities include Segment B congestion relief project construction along with ways to secure funding and the development of a finance plan for the SR37 corridor SLR adaption project.