WASHINGTON (Reuters) -The U.S. National Highway Traffic Safety Administration said on Thursday that it is opening an investigation into 2.88 million Tesla vehicles equipped with its Full Self-Driving system over traffic-safety violations after a series of crashes.

The auto safety agency said FSD - an assistance system that requires drivers to pay attention and intervene if needed - has "induced vehicle behavior that violated traffic safety laws".

The agency said it has reports of Tesla vehicles driving through red traffic lights and driving against the proper direction of travel during a lane change, while using the system.

RECALL COULD FOLLOW IF NHTSA FINDS SAFETY RISKS

NHTSA said it has six reports in which a Tesla vehicle, operating with FSD engaged, "approached an intersection with a red traffic signal, continued to travel into the intersection against the red light and was subsequently involved in a crash with other motor vehicles in the intersection."

NHTSA said four crashes resulted in one or more injuries.

Tesla did not immediately respond to a request for comment.

The investigation - a preliminary evaluation - is the first step before the agency could seek a recall of the vehicles if it believes they pose an unreasonable risk to safety.

NHTSA said it has identified 18 complaints and one media report alleging that Tesla vehicles, operating at an intersection with FSD engaged "failed to remain stopped for the duration of a red traffic signal, failed to stop fully, or failed to accurately detect and display the correct traffic signal state in the vehicle interface."

Some complainants said FSD "did not provide warnings of the system's intended behavior as the vehicle was approaching a red traffic signal."

Tesla's FSD, which is more advanced than its Autopilot system, has been under investigation by NHTSA for a year.

In October 2024, the agency began an inquiry into 2.4 million Tesla vehicles equipped with FSD after four reported collisions in conditions of reduced roadway visibility, such as sun glare, fog or airborne dust, including a 2023 fatal crash.