A report released on Monday by U.S. regulators maintains that automakers will fail to meet the 54.5 mpg corporate average fuel economy target set for 2025.

In the Draft Technical Assessment Report, the EPA, National Highway Traffic Safety Administration and California Air Resources Board assess the costs, technology and issues affecting efforts by the automotive industry to reduce greenhouse gas emissions.

The report indicates that automakers have been “adopting fuel economy technologies at unprecedented rates” and have been able to meet current regulations at or below costs estimated in 2012. Improvements in gasoline engines are also said to have lessened the reliance on sales of hybrid and electric vehicles to offset ratings.

However, despite a number of positive advancements, officials say that the 54.5 mpg goal has become unattainable as a result of low gas prices and increased demand for trucks and SUVs. Government estimates now project that the fleetwide average fuel economy will come in between 50 mpg and 52.6 mpg by 2025.

The EPA will finalize regulations for 2022 to 2025 model year vehicles by April 1, 2018.