A Waymo hit a child near an elementary school in Santa Monica

• US safety regulators opened a probe after a Waymo robotaxi struck a child near a school.
• The crash happened during school drop-off hours with kids, guards, and parked cars nearby.
• Waymo said its driverless system braked sharply, cutting speed before the child was hit.

Federal safety regulators have opened an investigation after a Waymo self-driving vehicle hit a child near an elementary school in Santa Monica, California.

The National Highway Traffic Safety Administration said the incident happened on January 23 during morning school drop-off hours, within two blocks of a school.

In its preliminary evaluation, NHTSA said the child ran into the street from behind a double-parked SUV and was hit by the autonomous vehicle, which was operating without a human safety driver.

In a statement published on its website, Waymo said it voluntarily notified NHTSA on the day of the incident and is cooperating fully with the agency's investigation.

Waymo said in its statement that as soon as the car detected the child, it "braked hard, reducing speed from approximately 17 mph to under 6 mph before contact was made."

The child suffered minor injuries, Waymo reported, according to NHTSA.

NHTSA is now examining whether Waymo's automated driving system exercised appropriate caution in a school zone and how the vehicle responded after the impact.

The investigation comes as Waymo faces heightened scrutiny over the safety of its autonomous vehicles.

In recent months, the company has dealt with a series of incidents, including a crash on Sunday in Los Angeles involving a Waymo vehicle driven by a human employee and a federal recall in May affecting more than 1,200 vehicles after robotaxis collided with chains or gates.

Last December, regulators also examined incidents in which Waymo vehicles stalled in busy intersections, disrupting traffic in San Francisco.