US regulators are questioning whether Tesla's (TSLA) steering wheel-free Cybercab can be temporarily fitted with traditional driving controls to meet federal safety standards, The Wall Street Journal reported Tuesday.

NHTSA asked whether temporary human-driver controls were part of Tesla's basis for certifying the Cybercab, the report said. The agency earlier this month opened an investigation into the vehicle's compliance, according to the report.

The Cybercab operates without pedals, mirrors or a steering wheel, while Tesla has said some versions can have manual controls for testing and safety validation, the report said.

NHTSA could order a recall if the vehicle is found noncompliant, according to the report.

Tesla did not immediately respond to MT Newswires' request for comment.

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