In the auto industry, it's generally assumed that as gas prices drop, so do sales of green cars.

Most consumers consider switching to more fuel-efficient, hybrid, or plug-in electric cars because of their anticipated lower fuel costs--but if gas is already inexpensive, the math doesn't look as good.

DON'T MISS: 2016 Toyota Prius Hybrid: Sportier, But Facing New Competition

So as the launch of the redesigned 2016 Toyota Prius hybrid looms, are executives praying for a rise in gas prices?

Toyota CEO for North America Jim Lentz isn't.

2012 Toyota Prius Plug-In Hybrid, Catskill Mountains, NY, Oct 2012

2012 Toyota Prius Plug-In Hybrid, Catskill Mountains, NY, Oct 2012

Loyal owners of previous generations will return for the new fourth-generation model--keeping sales strong regardless of cheap gas--he told industry trade journal Ward's Auto in a recent interview.

He said the roughly 2 million owners of current and prior Prius models are expected to return for the new one, and he consequently he thinks Toyota "is going to be fine."

Toyota also expects to lure some buyers away from competitors' hybrids, although those vehicles are tougher and more numerous than ever before.

ALSO READ: All-New 2016 Toyota Prius: What We Know So Far

The 2016 Prius will launch sometime next year, along with another high-profile green car from Toyota.

Lentz was also confident that low gas prices won't affect sales of the 2016 Mirai hydrogen fuel-cell car, mostly because Toyota only expects to sell a small number anyhow.

Lack of fueling infrastructure means Toyota is limiting sales to California for now. It expects to sell just 200 cars there in the fourth quarter of 2015, and 3,000 nationally by late 2017.

Just as current hybrid owners are expected to to stay loyal, Toyota anticipates prospective fuel-cell buyers to be committed to the technology.

Toyota Prius Plug-In Hybrid on the Nurburgring

Toyota Prius Plug-In Hybrid on the Nurburgring

As with the first-generation Prius, the company expects buyers to be early adopters who are particularly interested in the newness of the technology and in driving a car with low environmental impact.

However, consistently cheap gasoline could make it difficult to expand the hydrogen niche, or get significantly higher numbers of first-time hybrid buyers into the Prius fold.

MORE: 2016 Toyota Prius: Next Hybrid Aims For 55 MPG, More Room, Better Handling

The Prius will always have its fans, but as it tries to grow that fan base, Toyota now faces pressure from multiple angles.

Some consumers will find that cheap gas makes a hybrid less financially appealing, while others may shift instead to battery-electric cars or plug-in hybrids.

_______________________________________________

Follow GreenCarReports on Facebook, Twitter, and Google+.