For the United States to meet its climate goals, cars and trucks need to be made with improved fuel efficiency. But a trio of obstacles—low gasoline prices feeding consumer demand for SUVs, industry attacks, and a slow rate of technological advances—is thwarting those objectives.

The standards known as the Corporate Average Fuel Economy (CAFE) laid out by the Obama administration set the average new vehicle fuel economy for model year (MY) 2025 as 54.5 miles per gallon. Those standards apply to passenger cars, light-duty trucks, and medium-duty passenger vehicles. A government fact sheet states: “Over the lifetimes of the vehicles sold in MYs 2017-2025 standards, this program is projected to save approximately 4 billion barrels of oil and reduce GHG emissions by 2 billion metric tons.”

What kind of vehicles consumers are buying is key. As the Union of Concerned Scientists explains, “CAFE standards set the average new vehicle fuel economy, [emphasis mine], that a manufacturer’s fleet must achieve.”

And, according to reporting by Reuters on Wednesday,

Reuters also cited industry data showing that sales of SUVs, pickup trucks, and other larger vehicles in 2015 are up since last year. They now stand at almost 59 percent, up about five percent since 2014.

“Wednesday’s report from the Environmental Protection Agency is likely to show that trucks are becoming more efficient, but those gains are largely being offset by the shift in some buyers from cars to trucks,” Reuters adds.

In addition, to meet the efficiency standards set by CAFE, automakers can’t continue business-as-usual, new research shows. The findings by University of Washington and the Massachusetts Institute of Technology researchers show that technological advances by automakers from 1990 to 2009 were quite slow compared to those of the 70’s and 80’s.