TAM proposes several improvements for the interchange to improve traffic conditions and make it easier for all users to get to and through this interchange. The proposals add new features to the current Caltrans Tamalpais Drive Overcrossing project, including widening lanes, realigning on-ramps, and adding new bike and pedestrian structures. 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 concept focuses on the current Caltrans proposal, which includes replacing the two existing pedestrian spiral walkway ramps with new pedestrian loop ramps with stairways. TAM also proposes upgrading traffic signals and adding new class II bike lanes on Tamalpais Drive. An alternative plan would add a roundabout at the Tamalpais and San Clemente Drive intersection.

The long-term concept builds on the near-term concept by adding design features, such as realigning on- and off-ramps and restriping southbound US 101 to carry four through lanes. A new multi-use path on the north side of Tamalpais Drive and over US 101 will extend from Madera Boulevard to San Clemente Drive.