The purpose of the Transportation Element is to describe existing and projected conditions of the transportation system and County policy concerning transportation. The Element begins with a discussion of current transportation system performance and the trends that led to current conditions, including policy and program activities undertaken by local government. (Unless otherwise noted, 1991 is the base year for the discussion of current conditions.) The Element includes a projection of how the system would perform with the land use projections contained in the Community Development Element. In order to accommodate the travel demand associated with the land use projections, the Element specifies the improvements needed for achieving an acceptable level of service and how those improvements would be provided. The Element also includes objectives, policies, and programs which facilitate the planning and public review process for the transportation system.

The existing transportation system is able to meet the demands placed upon it, except during the morning and evening peak commute hours. During those times Highway 101 at Puerto Suello Hill and several arterials experience unacceptable congestion (Level of Service F). Congestion increased during the 1980's due to increased automobile use within Marin, a decline in transit use and carpooling to San Francisco, and limited increases in the capacity of Highway 101 and local arterials.

Projections of travel demand associated with the land use projections show that portions of Highway 101 and selected arterials would suffer severe congestion (Level of Service F) at Plan buildout unless there are increases in transportation system capacity. In order to meet the Plan goal of Level of Service D (or better), the capacity of the transportation system must increase. Recommended improvements include completing the High Occupancy Vehicle lanes from the Richardson Bay Bridge to the Sonoma County line, creating light rail transit service between Larkspur Ferry Terminal and Santa Rosa, increasing ferry service to San Francisco, building auxiliary lanes between selected freeway interchanges, and improving selected local streets.

If the recommended improvements are not funded by a combination of State and Federal transportation funds, Golden Gate Bridge District revenues, new local sales taxes, and traffic mitigation fees from local developers, then the cities and the County may need to consider revising the land use policies which lead to the need for transportation improvements. Public policy emphasizes setting and maintaining level of service standards, providing the necessary improvements to meet the level of service standards, and linking land use and transportation system decisions to achieve and maintain level of service standards.