https://www.federalregister.gov/documents/2023/04/11/2023-06869/petroleum-equivalent-fuel-economy-calculation https://www.federalregister.gov/documents/2023/04/

https://www.federalregister.gov/documents/2023/04/11/2023-06869/petroleum-equivalent-fuel-economy-calculation https://www.federalregister.gov/documents/2023/04/11/2023-06... Here's the NOPR, it includes background on where the number comes from.