The Sonoma County Travel Behavior Study (TBS), published in 2020, presents an analysis of vehicular travel during 2017 and 2018 that occurred within Sonoma County and the greater region, it analyzes critical gateways around the county boundary and extended distance visitor travel trends. The TBS Addendum document provides updated travel behavior for 2017, 2019, and 2022. These studies utilize Caltrans traffic counts, origin-destination mobile device data from StreetLight Data, Inc., and supplemental data, including the U.S. Census. StreetLight quantifies vehicle trips associated with residents, employees, and visitors, where those trips start and end, the length of those trips, travel times, and time of day. The TBS Addendum considers how the COVID-19 Pandemic and other external factors impacted the county’s travel patterns.

The goal of the TBS Addendum is to provide an updated evaluation of vehicular travel within Sonoma County based on data from traffic counts and mobile device data. The TBS Addendum provides SCTA and its member jurisdictions with several data sets that can support future planning and engineering activities as a robust data source and analysis. One shorter-term use will be the refinement and enhancement of the Sonoma County Travel Model. Longer-term uses can provide a valuable source of information to support upcoming general and specific plan updates and project analysis at the countywide and jurisdiction levels.