A new lawsuit accuses the U.S. government of being too slow to implement rules requiring that rear seat vehicle passengers be warned when they fail to buckle their seat belts.

In a complaint filed on Wednesday, two nonprofits said the National Highway Traffic Safety Administration (NHTSA) has done nothing to implement legislation signed in July 2012 by former President Barack Obama that required the warnings.

The Center for Auto Safety, and Kids and Cars Inc, said nearly 1,000 people are killed annually in the rear seats of U.S. passenger vehicles because they do not buckle up, and proper belt usage would lower the risk of death by 44 percent.

“No one disagrees that seat belts save lives,” Jason Levine, executive director of the Center for Auto Safety, said in a phone interview. “We don’t think the lives of people in the back seat are worth less than those in the front.”

The lawsuit seeks to require NHTSA, part of the Department of Transportation, to start the rulemaking process immediately and within one year implement a final rule, which was supposed to take effect by October 2015.

Transportation Secretary Elaine Chao was also named as a defendant. Her agency had no immediate comment.

Earlier this month, the Insurance Institute for Highway Safety said 91 percent of adults claim to always buckle up in the front seat, but just 72 percent use seat belts in the back.

The IIHS said one-fourth of the rear seat holdouts believed sitting in the back was safer. Smaller percentages said they did not use belts out of habit, because they forgot, or because they found belts uncomfortable or ill-fitting.

According to NHTSA, 35,092 people died in motor vehicle crashes in 2015, the most in seven years, but 13,941 lives were saved by seat belts.

NHTSA also said seat belts saved more than 343,000 lives from 1976 to 2015, and would have saved another 368,000 had everyone worn them.

New Hampshire is the only U.S. state that does not require adults to buckle up.

While not excusing the Obama administration for failing to implement seat belt warnings, Levine said the persistent absence looks like an example of the Trump administration “looking to delay rules rather than issue a mandated rule.”

The case is Kids and Cars Inc et al v. Chao et al, U.S. District Court, District of Columbia, No. 17-01660. (Reporting by Jonathan Stempel in New York; Editing by Tom Brown)