Tesla didn’t respond to a request for comment on the NHTSA upgrading its investigation. The company’s shares closed down 0.9%, erasing earlier gains. The stock has fallen 32% this year.
In a document posted to its website, the NHTSA said its probe now applies to an estimated 830,000 vehicles, roughly 65,000 more than when it started evaluating the potential defect in August. Three more crashes involving Teslas hitting first responder vehicles have occurred since the investigation started, the latest occurring in January.
NHTSA said in the document that it will “explore the degree to which Autopilot and associated Tesla systems may exacerbate human factors or behavioral safety risks by undermining the effectiveness of the driver’s supervision.”
The agency also dispelled the notion that driver misuse of Autopilot may preclude it from making a defect determination. “This is particularly the case if the driver behaviour in question is foreseeable in light of the system’s design or operation,” the NHTSA said.
Tesla has for years marketed certain assistance features as Full Self-Driving and charged customers thousands of dollars to beta-test the technology. In a statement on Thursday, the NHTSA reiterated that “no commercially available motor vehicles today are capable of driving themselves”.
Autopilot is facing increased scrutiny from the NHTSA on another front. Last week, the agency disclosed the number of complaints it’s received about Teslas suddenly braking at high speeds had more than doubled since it opened a defect investigation into that issue in February.
The NHTSA has given Tesla until June 20 to respond to pages of questions and information requests related to that probe. The agency is also planning to release data in the coming weeks about crashes involving automated-driving features roughly a year after it issued a standing general order for automakers to begin sharing information.
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