“Tesla withdrew from the party agreement with the NTSB because it requires that we not release information about Autopilot to the public, a requirement which we believe fundamentally affects public safety negatively. We believe in transparency, so an agreement that prevents public release of information for over a year is unacceptable. Even though we won’t be a formal party, we will continue to provide technical assistance to the NTSB.”

Source : Tesla booted from investigation into fatal Autopilot crash – The Verge