WASHINGTON — Major automakers said on Wednesday they have agreed to equip nearly all U.S. vehicles with systems to remind motorists of passengers in the back seat, by model year 2025, in an effort to avoid deaths of young children left behind in hot cars.

The announcement on so-called rear seat reminder systems comes as the U.S. Congress has been debating the issue. In July, the Senate Commerce Committee passed by voice vote legislation to eventually require automakers to install technology on new vehicles alerting exiting parents to check for children in the back seat.

The automakers from two trade groups representing nearly all automakers said the companies are committing to include audible and visual alerts on vehicles by the 2025 model year but could get an additional 12 months for vehicles about to be redesigned and could exempt emergency motor vehicles.

The 20 automakers taking part represent nearly 98% of all U.S. vehicle sales.

The automakers include General Motors Co, Ford Motor Co, Volkswagen AG, Toyota Motor Corp, Hyundai Motor Co and Honda Motor Co.

Fiat Chrysler Automobiles NV said it will eventually adopt the reminder technology on all vehicles worldwide but said timing by region will vary.

GM has had a system on some U.S. vehicles since 2016 that provides audible alert and a visual reminder on the vehicle dashboard to check for a child before exiting.

Lawmakers say more than 800 children in parked vehicles have died from heatstroke in the United States over the last two decades.

The systems generally operate to alert a driver to the presence of a child if a rear door was opened at the start of a trip. Some safety advocates want a more advanced system that would detect the actual presence of a child in the back seat.

U.S. Senator Roger Wicker, a Republican who chairs the Commerce Committee, said in an interview the voluntary agreement makes the legislation unnecessary. Under the legislation being considered, the National Highway Traffic Safety Administration (NHTSA) would be compelled to write regulations and then automakers would have at least two years' lead time.

"This gives us essentially everything we've asked for and it does it sooner," said Wicker, who added the Transportation Department plans to use some discretionary funds for a public information campaign. "It is a huge win."

NHTSA typically takes years to write regulations. For example, a proposal to require automakers to send email notifications of recalls has been pending for more than three years.

Wicker's bill would also direct states to use a portion of highway safety program funds to educate the public on the risks of leaving a child or unattended passenger in a vehicle, and require the Transportation Department to conduct a third-party study on retrofitting existing passenger motor vehicles.

U.S. Representative Jan Schakowsky, a Democrat who cosponsored the legislation, noted earlier this year that many newer vehicles alert drivers if they leave their keys behind. “You should get a warning if you leave a child in the car,” she added.