DETROIT — Automakers appear to be on the verge of a rare victory in their long-term effort to reduce government regulations on new cars and trucks.

As soon as Tuesday, the Trump administration is expected to announce its agreement with the major auto companies that future mileage and emissions standards should be overhauled to reflect the growing consumer demand for larger, less fuel-efficient vehicles such as pickup trucks.

Any decision by the Environmental Protection Agency and Transportation Department to reopen a review of the regulations could ease the pressure on the industry to meet the current target of 54 miles per gallon for vehicle fleets by 2025.

Individual carmakers may react differently to a rollback of the federal standards. Some companies, for example, will continue to pursue electric car programs, while others may scale back their plans. And over all, the industry is likely to continue to make incremental fuel-economy improvements as new models are introduced, primarily as a selling point to consumers.