WASHINGTON - President Donald Trump is expected to relax ambitious Obama-era vehicle mileage standards and raise the ceiling on damaging fossil fuel emissions for years to come, gutting one of the United States single-biggest efforts against climate change. The Trump administration is expected to release a final rule Tuesday on mileage standards through 2026, watering down a tough Obama mileage standard that would have encouraged automakers globally to ramp up production of electric vehicles and more fuel-efficient gasoline vehicles.