WASHINGTON - The U.S. National Highway Traffic Safety Administration said on Friday it is seeking more information in its investigation into Amazon.com's self-driving Zoox vehicles due to unexpected braking leading to two rear-end collisions.

The agency, which opened a probe into the crashes this month, said it is seeking video of the crashes and documents from Zoox related to the vehicles.

NHTSA said it "is concerned that vehicles exhibiting unexpected rapid braking may increase the risk of crash" and added the "risk is particularly acute to road users behind the Zoox vehicles who are unable to reasonably anticipate or react to the unexpected sudden braking."

  - Reuters