On Tuesday, the U.S. National Highway Traffic Safety Administration ordered Tesla Inc. (TSLA  ) to answer 21 detailed questions by Sept. 30 on how it self-certified its Cybercab robotaxi as compliant with federal safety standards.

According to the order, NHTSA's Chief Counsel, Peter Simshauser, issued the detailed request Sept. 10 under Audit Query AQ26002, which the agency opened Sept. 3 after Tesla began commercial Cybercab deployment in Austin, Texas.

The order stated responses must come under oath from a Tesla officer.

Regulators Zero In on Driver Controls

Noncompliance risks civil penalties up to $139.35 million and criminal penalties of up to 15 years in prison, or both, NHTSA said.

Regulators want to know whether temporarily installed human driver controls factored into Tesla's compliance certification and how removing such controls complies with federal "make inoperative" rules.

The agency also asked whether touchscreen controls let occupants move the vehicle and how Tesla justifies compliance with Federal Motor Vehicle Safety Standard No. 135, which requires service brakes activated by a foot pedal.

Missing Mirrors, Turn Signals Draw Scrutiny

The order also asks Tesla to detail whether the Cybercab has mirrors, a self-canceling turn signal and a shift-position display required under current standards. The two-seater also lacks a steering wheel, brake pedal and accelerator pedal.

The scrutiny comes as Tesla and Alphabet Inc.'s (GOOG  ) (GOOGL  ) Waymo push federal regulators to eliminate traditional driver-control requirements for autonomous vehicles entirely. The Trump administration has signaled support for this regulatory shift. Safety advocates, however, have opposed the change. They argue that any exemptions should wait until robotaxi makers can prove their vehicles are safe without human backups.

In July, Amazon.com Inc.'s (AMZN  ) Zoox unit won a similar exemption, an industry first.

Growing Pains Meet Growth Plans

The order lands as Tesla's rollout also faces its own growing pains.

A rider recently reported that a short trip from 99 Ranch Market to The Domain in north Austin, normally quick via highway, stretched to roughly 70 minutes after the Cybercab avoided highways instead.

After the Austin launch, prominent tech analyst and Deepwater Asset Management co-founder Gene Munster predicted Tesla could add roughly 300 Cybercabs to its Austin fleet within a month, calling the rollout bullish.

Trading Metrics

Tesla has a market capitalization of $1.40 trillion, a 52-week low of $297.38 and a 52-week high of $498.83.

Price Action: TSLA stock closed the regular session on Tuesday at $356.58, down 0.67%, according to Benzinga Pro data. Tesla shares have dropped 20.71% since the start of the year to date.

Benzinga's Edge Stock Rankings indicate that Tesla stock is experiencing short-term upward movement along with consolidation in the medium and long term.