Fiat Chrysler Automobiles and Ford Motor Co. came out against President Trump's bid to relax strict fuel economy standards approved during the Obama administration, but said the initial rules didn't consider increasingly popular utility sales and continuing lower fuel prices, the automaker said in feedback submitted as part of the public review.

The U.S. Environmental Protection Agency and National Highway Traffic Safety Administration began hearings this week, including one in Dearborn, Michigan on Tuesday, on Trump's SAFE (Safer Affordable Fuel-Efficient) Vehicles rule that would roll back fuel efficiency and greenhouse gas emissions standards for vehicles produced from the 2021 to 2026 model years. It would freeze Corporate Average Fuel Economy (CAFE) standards at 2020 levels for those model years. The EPA is also proposing to withdraw a waiver granted to California for the greenhouse gas and zero emissions vehicles sections of the regulations.

"In model year 2016, for the first time since the new standards were put in place, the industry as a whole could not comply with the fleet standards without using credits," said Steve Bartoli, FCA's vice president of global fuel economy, in submitted comments. "FCA supports the policy choice in favor of ongoing fuel economy improvements in the fleet, but that policy needs to be based on market realities as they have evolved since 2012."

Ford's global director of sustainability and vehicle environmental matters, Bob Holycross, echoed the sentiment, saying in his testimony that the company does not support "standing still," reports the Detroit News.

"We need a consistent, stable regulatory framework in which to make these capital-intensive investments, including policies that will help drive demand for emerging technologies," he said.

Part of why automakers have had difficulty complying with current standards without using credits is due to the higher SUV sales, because these vehicles require more energy, according to FCA.

Original forecasts showed cars increasing from 50% to 57% of annual vehicle sales by 2025. Instead, car sales fell to 36% of total sales in 2017, while sales of SUVs increased from 30% to more than 40%. Gasoline prices were predicted to be more than $4 per gallon by 2018, and today's national average price reached $2.85 on Sept. 24, according to AAA.

"A utility or crossover vehicle with the same powertrain and technology as a sedan with the same footprint will require more energy — a trade-off consumers are willing to make for the versatility of a crossover or SUV. This is a primary contributing factor to the growing industry compliance gap," according to an FCA release.

Consumers have also been reluctant to purchase the range of electrified or hydrogen-powered vehicles produced by manufacturers. In the past decade, automakers have nearly tripled the number of available electrified vehicles such as gasoline-electric hybrids, plug-in hybrid electric vehicles, battery-electric vehicles, and fuel cell vehicles. The combined market share of these vehicles has remained nearly flat at 3% and 1.5% for the most strongly electrified vehicles.

General Motors and other manufacturers haven't made their comments public about Trump's proposed rule.