Tesla Probe Puts Spotlight on Four-Year Vacancy at U.S. Watchdog

The federal regulator charged with keeping U.S. roads safe is now in its fourth year without a permanent administrator, and President Joe Biden hasn’t nominated anyone as the agency undertakes a politically fraught investigation of Tesla Inc.

The absence of a Senate-confirmed leader could complicate the National Highway Traffic Safety Administration’s effort to craft rules for a surge of driver-assistance technologies and other automotive features -- some of which have been linked to deadly accidents.

The agency last month announced it was undertaking a formal investigation into Tesla’s Autopilot system after almost a dozen collisions at crash scenes ...