The National Academies of Sciences, Engineering, and Medicine (NASEM) Committee on Assessment of Technologies for Improving Fuel Economy of Light-Duty Vehicles, Phase 3 was tasked by The National Highway Traffic Safety Administration (NHTSA) with providing estimates of the potential cost, fuel economy improvements, and barriers to deployment of technologies for improving fuel economy in 2025-2035 light-duty vehicles. The National Academies Committee was investigating the state of vehicle mass reduction technology readiness and the impact of mass reduction on fuel economy while maintaining vehicle performance and safety requirements.