US regulators probe Amazon-backed Zoox after 2 of its cars unexpectedly braked and caused crashes

• Amazon-backed Zoox is under investigation following two crashes involving its self-driving tech.
• The NHTSA said two motorcyclists collided with Zoox vehicles after they braked unexpectedly.

Another self-driving car company is facing an investigation over safety concerns.

The National Highway Traffic Safety Administration said on Monday it had opened an investigation into Zoox, which was acquired by Amazon for a reported $1.2 billion in 2020, after two vehicles equipped with the company's self-driving systems collided with motorcyclists after braking unexpectedly. Reuters was first to report the news.

Both crashes resulted in minor injuries, according to the regulator, and the two Toyota Highlander SUVs involved were both operating in an autonomous driving mode in the lead-up to the collision.

Zoox is the latest company to face questions from regulators over the safety of its self-driving technology.

Tesla recalled two million vehicles late last year after the NHTSA found that the company's Autopilot system did not do enough to prevent misuse. The Elon Musk-run automaker is now facing a further investigation into whether that recall was adequate.

Cruise — majority owned by General Motors — meanwhile, has been banned from operating from California and faces a federal investigation after an incident in which a pedestrian was dragged 20 feet along the road under one of its vehicles.

Zoox unveiled its first electric robotaxi in 2020, a "carriage-style" vehicle without a steering wheel.

The company has been testing it in California, with the ambition of launching an autonomous ride-hailing service in the future.

However, no commercial release date for the vehicle has been announced, and Zoox is currently under an additional NHTSA investigation into its self-certification tests for the robotaxi model.

A Zoox spokesperson said the company was currently reviewing the NHTSA's request for information and did not have more information to share.

"Transparency and collaboration with regulators is of the utmost importance, and we remain committed to working closely with NHTSA to answer their questions," they said.