Amazon.com’s robotaxi unit, Zoox, announced on Wednesday its plans to start testing autonomous vehicles in Austin, Texas, and Miami, marking its first trial sites outside the western United States.

Zoox will deploy its test fleet of retrofitted Toyota Highlanders, equipped with human safety drivers, in small areas near the business and entertainment districts of both cities. This expansion follows Zoox’s ongoing testing in California and Nevada, where it uses self-designed autonomous vehicles without steering wheels and pedals, accommodating four passengers with two facing each other.

This announcement comes amid an investigation by the National Highway Traffic Safety Administration (NHTSA) into 500 Zoox vehicles equipped with automated driving systems after two crashes.

Austin and Miami will become Zoox’s fourth and fifth public testing locations, adding to its existing operations in San Francisco, Las Vegas, and Seattle. Zoox stated that it will not offer public rides in Austin and Miami yet but is exploring several cities for commercial offerings after its initial launch in its target markets of Las Vegas and San Francisco.

Other self-driving robotaxi companies, including General Motors’ Cruise and Alphabet’s Waymo, are also under investigation by the NHTSA regarding the performance of their autonomous vehicles. Cruise recently resumed operations in Dallas, Texas, with a small fleet of human drivers after pausing operations due to an incident in San Francisco involving one of its robotaxis last October.