(AP) – Federal regulators are clearing the way for robotaxis to operate without steering wheels or eventually even brake pedals as the rules start to catch up to the evolving technology.

Amazon’s fully autonomous Zoox vehicles got approval Thursday to begin charging customers for rides in the specially designed boxy cars that feature four inward-facing seats once they secure state and local approval. Zoox has already been offering free rides in Las Vegas and San Francisco since last year.

The National Highway Traffic Safety Administration also proposed a rule last month to allow robotaxis to operate without brake pedals, but that proposal is still pending. Administrator Jonathan Morrison said his agency wants to clear the way for the safe development of autonomous vehicles.

“By removing unnecessary barriers to innovation, developing industry guidance, and providing strong enforcement oversight while we create performance requirements, NHTSA is taking a balanced approach to AV regulation,” Morrison said in a statement. “These advancements will ensure that the United States continues to lead the world in AV technology in a safe and responsible manner.”

Zoox and Tesla are working to catch up to the industry-leading Waymo that already operates in multiple cities. Waymo is owned by Google’s parent company, Alphabet.

Zoox CEO Aicha Evans said this approval is an important milestone for autonomous vehicles.

“This achievement reflects a shared commitment to enabling innovation while maintaining the highest standards of safety,” Evans said.

Amazon hopes to eventually produce as many as 10,000 robotaxis a year at a plant near Silicon Valley as it works to challenge Waymo. Amazon paid $1.2 billion to acquire self-driving startup Zoox. Initially, Zoox will only be allowed to deploy up to 2,500 vehicles without steering wheels over the next two years as it works to prove the technology is safe. The company said that more than half a million people have already ridden in its vehicles.