Musk has complained that U.S. regulations are too onerous and are holding back the development of self-driving cars. Ethics experts are worried that once President-elect Donald Trump takes office, Musk will push him to ease oversight of Tesla, which just suffered its first decline in annual sales in more than a decade.

The National Highway Traffic Safety Administration announced it is investigating nearly 2.6 million Tesla vehicles over a remote driving feature.

The National Highway Traffic Safety Administration is probing about 2.6 million Teslas after regulators discovered that a feature on multiple vehicle models was tied to crashes. The feature, known as "Actually Smart Summon" is intended to have the car park itself and pick up its owner using a button on the Tesla app.

The agency has previously investigated earlier versions of Smart Summon, which is meant to let a Tesla vehicle park itself or fetch a driver via remote app command.

The National Highway Traffic Safety Administration (NHTSA) is investigating 2.6 million Tesla vehicles due to reports of accidents related to the Smart Summon and Actually Smart Summon features.

Tesla is under investigation by the NHTSA once again, this time over the automaker's "Actually Smart Summon" feature, which allows users to recall their Tesla to their location remotely, for example across a parking lot.