The State of California has many air quality, climate, and community risk reduction goals to achieve over the next thirty years. CARB staff is developing the 2020 Mobile Source Strategy to take an integrated planning approach to identify the level of transition to cleaner mobile source technologies needed to achieve all of California’s targets. Mobile sources and the fossil fuels that power them continue to contribute a majority of emissions of diesel particulate matter as well as smog- and particulate‑forming pollutants such as oxides of nitrogen (NOx), and the largest portion of greenhouse gas emissions in California. The actions contained in the Mobile Source Strategy will deliver broad environmental and public health benefits, as well as support much needed efforts to modernize and upgrade transportation infrastructure, enhance system-wide efficiency and mobility options, and promote clean economic growth in the mobile sector.