Federal regulators are opening an investigation into whether Tesla's new steering-wheel-free taxis comply with safety rules, a day after the company began offering rides in the vehicles.

The National Highway Traffic Safety Administration said it was looking into whether Tesla was in full compliance with federal rules when it deployed so-called Cybercabs in Austin, Texas, given that the two-seat cars lack the steering wheels, mirrors and brake pedals typically required in vehicles.

The head of the company, Elon Musk, kicked off the Cybercab service in Austin on Thursday with fanfare, sending dozens of the futuristic taxis onto city streets and holding a launch event for invitees.