North South Greenway Gap Closure Project

LARKSPUR & Corte madera, California

The North-South Greenway Gap Closure Project closes a key gap in the local and regional non-motorized transportation network between the Central Marin Ferry Connector Bridge (CMFC) and the existing multi-use paths at the intersection of Old Redwood Highway and Wornum Drive. The Project is bring delivered in two segments—the Northern Segment along US 101, and the Southern Segment along the future Sonoma-Marin Area Rail Transit (SMART) corridor.

The Northern Segment project replaces the existing narrow sidewalk on the US 101 Northbound off-ramp over Corte Madera Creek with a wider multi-use pathway. A new multi-use pathway along Old Redwood Highway is also included in the project to connect to the existing Greenbrae Highway 101 Pedestrian Overcrossing (POC). To design the connection over Corte Madera Creek, SGA met navigational requirements for watercraft, included architectural treatments for the bridge’s bent caps, and used coffering to minimize the visual massing of the structure. Where environmental sensitivity to the creek is necessary at night, bridge lighting is incorporated into the railings to illuminate the traveled way and prevent spillover of light. At the Greenbrae POC touchdown area, SGA’s design includes seating, architectural lighting, and pavement treatments for both safety and aesthetics.

The Southern Segment project proposes to connect to the Northern Segment project at the north end of Old Redwood Highway and travel east, via a future public easement through private property, to the SMART right-of-way that currently consists of an elevated earthen embankment with abandoned railroad tracks and dirt pathways. The project proposes to construct a new trail south along SMART'S right-of-way, and southwest along Corte Madera’s right-of-way, until intersecting with the existing bicycle and pedestrian trails at Old Redwood Highway and Wornum Drive. A variety of constraints and considerations have influenced the project design, including minimizing disruptions to adjacent private residences, preventing access into sensitive marshland habitat, and grading the pathway for proper drainage of stormwater.

For the Northern Segment, environmental analysis and final design were completed in 2020, and construction began in early 2021. The first phase of construction involves work within the Caltrans right-of-way, while the second phase involves work within the City of Larkspur. For the Southern Segment project, the use of the SMART right-of-way has been secured, but acquisition of a public access easement through private property is still required. Preliminary engineering and environmental review for the Southern Segment has been suspended while the Transportation Authority of Marin, the Project Sponsor, resolves funding constraints of the overall North-South Greenway Gap Closure Project.

For more information, visit: 
https://www.nsgreenwaygapclosure.com

Status: In Construction (Northern Segment)
SGA's Scope of Work:  Project Architect, Public Outreach
Client: Transportation Authority of Marin
Agencies Involved: Caltrans, ABAG
Prime Consultants: SGA (Southern Segment); Moffatt & Nichol (Northern Segment)