San Marin Drive / Atherton Avenue

The interchange at Atherton Avenue is in the city of Novato. Drivers use this interchange to get to residential neighborhoods, a nearby office park, the Novato San Marin SMART (Sonoma Marin Area Rail Transit) station, and downtown Novato via Redwood Boulevard. TAM’s study found several features at the interchange that could be improved, including the short acceleration-and-merge lengths at the on-ramps, noncontinuous bike paths, and sidewalk and lane widths that do not meet current standards. These and other limitations are described in the Existing Conditions, Constraints, and Opportunities Report below.

Interchange Improvements

TAM proposes several improvements for the interchange to improve the flow of traffic and make it easier for all users to get to and through this interchange. Proposed projects include restriping, adding new bike lanes and widening part of the Atherton Avenue overcrossing. To gain an important understanding of the interchange area, the study examined the following:

  • Existing Infrastructure
  • Transit Routes and Intermodal Connectivity
  • Weekday AM & PM Peak Period Congestion
  • Crash Type and Severity
  • Environmental Constraints

 

Many of the study’s recommended changes will make the interchange easier to use for drivers, bicyclists, pedestrians, and people using public transit. The proposals will also increase safety at the interchanges and on surrounding streets and pathways, allowing for smoother travel to, from, and across Highway 101 and local roads.

The near-term improvement concept focuses on increasing safety and making it easier to get around the interchange. Existing traffic signals will be upgraded and interconnected. Class II bike lanes will be added throughout the area, several lanes will be restriped, and more dedicated turn-lanes will be added to intersections.

The long-term concept will build on some of the near-term proposals, including adding turn lanes and widening roadways to meet traffic demands. The Atherton Avenue overcrossing will be widened above the SMART corridor to provide a second westbound left-turn lane, the sidewalk on the south side will be widened, and new bike lanes will be added on both sides of the overcrossing.

Public and Agency Input

Between March and April 2021, TAM surveyed residents of Marin County to collect input about the 12 selected interchanges. More than 2,750 people responded to the survey. The survey was launched to gather the public’s thoughts and priorities on improvements to the interchange. TAM has incorporated the feedback we received to ensure the project reflects community values and preferences.

In the survey, 41 people commented on San Marin Drive/Atherton Avenue. Residents rated the level of importance for eight potential improvements on a 5-point scale ranging from not important to most important. The interchange report includes a summary of the survey results and comments received.

Most respondents said reducing traffic congestion in the area is the most important improvement to this interchange.

Reduce traffic congestion

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Make it safer to walk around this interchange

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Make it safer to bike around this interchange

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Improve lighting and security

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Make it easier to drive to and from this interchange

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Improve the quality and access to bus stops near this interchange

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Increase Park and Ride capacity

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Improve environmental sustainability and resiliency

0 %
Low
Importance
0 %
No
Opinion
0 %
High
Importance

Walking across most of these intersections is, at best, dangerous, so better coordination amongst the traffic lights would be appreciated.

Comments regarding this interchange?
Your remarks will be noted and saved for possible future phases of improvement.