Cars could get triple current fuel economy figures by 2035 if U.S. drivers will accept smart technology over pure horsepower, a researcher says.

As federal regulators prepare the next round of fuel economy mandates, John DeCicco of the University of Michigan and the Michigan Memorial Phoenix Energy Institute says the most cost-effective answer is steady progress in advanced combustion engines and hybrid drive, an institute release said Tuesday.

DeCicco says the solution is a "revolution by evolution" rather than politically trendy breakthrough technologies that will remain too expensive for most consumers.

"If we really prioritize efficiency, we can get just as far with less sticker shock," he said. "Evolutionary change can be of profound consequence for cutting oil use and greenhouse gas emissions, and do so with manageable costs and minimal risks for automakers."

Optimizing internal combustion engines and more adoption of grid-free hybrids will enable new fleet efficiency levels to reach 52 mpg by 2025 and 74 mpg by 2035, he predicts.

"The fleet I've modeled for 2025 does not give up any of the performance and creature comforts consumers already enjoy," he said. "You don't have to go back to being Fred Flintstone, but you will see lower fuel costs instead of ever more mass and muscle."