In recognizing the potential for large, damaging impacts from climate change, California enacted Executive Order S-03-05, requiring a reduction in statewide greenhouse gas (GHG) emissions to 80% below 1990 levels by 2050. Given that the transportation light-duty vehicle (LDV) segment accounts for 28% of the state's GHG emissions today, it will be difficult to meet the 2050 goal unless a portfolio of near-zero carbon transportation solutions is pursued. Because it takes decades for a new propulsion system to capture a large fraction of the passenger vehicle market due to vehicle fleet turn-over rates, it is important to accelerate the introduction of these alternatives to ensure markets enter into early commercial volumes (10,000s) between 2015 and 2020. This report summarizes the results and conclusions of a modeling exercise that simulated GHG emissions from the LDV sector to 2050 in California. Specifically, the analysis addressed two policy questions: (1) what fraction of the on-road fleet in 2050 needs to be zero-emission vehicles (ZEVs) 1 in order for the LDV sector to achieve an 80% GHG reduction, and (2) what annual ZEV sales are necessary between 2015 and 2025 to initiate these fleet volumes? Two scenarios were developed revealing how difficult it will be to achieve this goal. Scenario 1 achieves a 66% reduction in GHG emissions by 2050 using aggressive assumptions. This scenario assumes ZEV sales reach a quarter of a million units annually by 2025 and become 100% of new vehicle sales by 2050. Scenario 2 was developed to show what would be required to achieve the full 80% GHG goal. To achieve this, two key parameters were modified with more aggressive and less certain assumptions. A steeper ZEV sales projection was simulated that achieves half a million ZEVs annually by 2025 and becomes 100% of new vehicle sales by 2040. Additionally, the availability of biofuels was increased to 1.7 billion gallons gasoline equivalent (BGGE), where it was limited to 1 BGGE in Scenario 1.