The U.S. government's auto safety watchdog has closed an investigation into Tesla electric car battery fires after the company agreed to install more shields beneath the cars.
Tesla says the shields will prevent roadway debris from damaging batteries and possibly causing fires.
The company will retrofit Model S cars sold in the U.S. with the new shields. It sold about 22,000 through February.
The National Highway Traffic Safety Administration says the shields and raising the ride height should reduce underbody damage and fire risk. Tesla says the action is not a recall.
The company says it will add an aluminum bar, a titanium plate and another piece of aluminum. The shields are designed to ward off the type of debris that caused fires in two cars last year.