The federal agency responsible for traffic safety, which has been investigating whether self-driving technology in Tesla vehicles played a role in the death of a pedestrian, will fire a “modest” number of employees, an agency spokesman said late Friday.

The agency did not say whether any of the fired employees were involved in investigations of Tesla, whose chief executive, Elon Musk, is leading the Department of Government Efficiency established by President Trump.

The efficiency department has been forcing layoffs at numerous government agencies as part of an effort to reshape the federal bureaucracy. Mr. Musk has retained control of Tesla while spending much of his time in Washington.

The National Highway Traffic Safety Administration has three active investigations of Tesla, according to agency documents, including one examining whether the company’s autonomous driving software is prone to failure when visibility is poor.

The layoffs at the traffic safety agency, which has less than 1,000 employees, were reported earlier by The Washington Post. Even after the layoffs, the agency continues to employ more people than at the beginning of the Biden administration, the agency said in a statement.

“The last administration grew NHTSA by a whopping 30 percent,” the agency said in a statement.

“We have retained positions critical to the mission of saving lives, preventing injuries, and reducing economic costs due to road traffic crashes,” the agency said. “We will continue to enforce the law on all manufacturers of motor vehicles and equipment.”

Tesla did not respond to a request for comment.

One of the investigations into Tesla is based on four accidents involving technology that the carmaker calls supervised full self-driving, which can steer, brake and navigate Tesla cars in some situations. In one of the crashes, a Tesla struck and killed a pedestrian, according to agency documents. In another of the accidents, a person was injured.

Tesla’s self-driving technology relies on cameras to survey a car’s surroundings, in contrast with competitors like Waymo, a unit of the same company as Google, that also uses lasers and radar to recognize objects.

The traffic safety agency has been looking into whether Tesla’s technology failed when visibility was poor because of glare from the sun, fog or dust.

Mr. Musk has often argued that Tesla self-driving technology is safer than human drivers.

The technology is also crucial to Tesla’s future and share price. As Tesla sales have flagged, falling 1 percent last year even as the global market for electric vehicles rose 25 percent, Mr. Musk has shifted the company’s focus to autonomous driving technology and plans for a self-driving taxi.

The technology will help make Tesla the most valuable company in the world by far, Mr. Musk told investors last month.