When most people think about clean energy, they think of wind and solar providing their homes and workplaces with electricity. But the transportation sector — which includes cars, trucks and airplanes — recently overtook the electricity sector as the leading source of greenhouse gases in the United States.

There are tremendous opportunities to reduce emissions from the transportation sector, all while making more user-friendly products. Take electric vehicles. If Elon Musk’s vision comes true, Americans will be able to charge their cars with electricity generated by rooftop solar panels, saving consumers money on gas and power. It’s not just consumers that stand to benefit from clean transportation. The US Navy is testing jets powered by advanced biofuels that will help give it a strategic and operational advantage.

But not everyone wants the transportation sector to innovate. Policymakers and auto manufacturers are chipping away at the incentives and regulations that are transforming the transportation sector.

As the New York Times reported, states across the country are attacking the incentives that have driven the growth of electric vehicles. The mechanisms differ slightly from state to state, but include repealing or letting expire tax credits for electric vehicles, or slapping EV owners with fees. Some of these state-level initiatives are funded by Koch-backed groups, which are waging a war on electric vehicles.

This week, President Trump traveled to Detroit to announce that he is reopening a review of the fuel economy standards for the years 2022 to 2025. The automakers have been vocal to the current President about the need to relax the requirements, even though automakers could easily meet the requirements and likely exceed them. The standards promise annual benefits of $19.5 billion from fuel cost savings and improved public health.

At the behest of automakers, China is considering delaying a requirement on electric vehicle production that would require battery electric and plug-in hybrid vehicles to make up 8 percent of sales beginning in 2018, increasing to 12 percent by 2020.

This is hardly a new dilemma. Policymakers have long fought entrenched interests to advance technology. Forty years ago, automakers resisted airbags, and only began to comply after the Supreme Court required it.

The shift to a low-carbon transportation system is inevitable. Bloomberg New Energy Finance estimates that falling costs for batteries will make the electric cars cheaper to own than conventional cars by 2025. The forthcoming Chevy Bolt and Tesla Model 3 will give Americans a taste of what affordable, long-range electric vehicles can do. Soon enough, their gas-guzzling counterparts may be a thing of the past.

Courtney St. John and Steve Hargreaves write for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture. You can follow them @shargrea and @CourtSaintJohn.