This polygon shapefile contains regional traffic analysis zones (RTAZ) for the San Francisco Bay Area in California. These data have ben clipped to the shoreline for cartographic representation. The California Metropolitan Transportation Commission (MTC) maintains a set of regional travel analysis zones for use in MTC planning studies. These travel analysis zones (TAZs) are typically small area neighborhoods or communities that serve as the smallest geographic basis for travel demand model forecasting systems. From time to time, MTC updates the regional travel analysis zone system to reflect changes in decennial census geography, changes in computing capability, and forecasting needs for particular corridor studies. The original MTC zone system, with 290 zones, was created in 1965 by planners of the MTC predecessor agency, the Bay Area Transportation Study Commission. Census Traffic Analysis Zones, (CTAZ) which range in size from multiple-block level in downtown San Francisco, Oakland, and San Jose to block group and tract level in suburban and rural areas of the region are meant to nest within the RTAZ system. This layer is part of the Bay Area Metropolitan Transportation Commission (MTC) GIS Maps and Data collection.This dataset is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data.