"In each of our investigations involving a Tesla vehicle, Tesla has been extremely cooperative on assisting with the vehicle data," an agency spokesman told the Washington Post. "However, the NTSB is unhappy with the release of investigative information by Tesla. The NTSB is looking into all aspects of this crash including the driver's previous concerns about the Autopilot."

At this time the NTSB needs the assistance of Tesla to decode the data the vehicle recorded. In each of our investigations involving a Tesla vehicle, Tesla has been extremely cooperative on assisting with the vehicle data. However, the NTSB is unhappy with the release of investigative information by Tesla. We will work to determine the probable cause of the crash and our next update of information about our investigation will likely be when we publish a preliminary report, which generally occurs within a few weeks of completion of field work

In the latter statement, the board is referring to comments from Huang's family to San Francisco TV station KGO-TV. They said he had brought concerns to a Tesla dealership that his Model X had previously swerved toward the same median where the accident happened.

Autopilot is a semi-autonomous mode that can maintain cruise speeds and follow distances and automatically change lanes under certain conditions. However, Tesla specifies that drivers must keep their hands on the wheel and be ready to take control back. If the system detects a hands-off state for a set time, Autopilot will warn the driver before disengaging. (It's fairly easy to fool it, however.)

By issuing the statement on Friday, Tesla implied that Huang had not followed its guidelines, adding that the accident was exacerbated by a highway crash attenuator that had recently been crushed in a previous accident and not yet reset.

The NTSB took umbrage to Tesla's preliminary justification of the accident, saying that the investigation is still ongoing. "At this time the NTSB needs the assistance of Tesla to decode the data the vehicle recorded," said NTSB spokesperson Chris O'Neil. "We will work to determine the probable cause of the crash and our next update of information about our investigation will likely be when we publish a preliminary report, which generally occurs within a few weeks of completion of field work."