Tesla Inc TSLA shares slipped lower Friday after a U.S. government department said it would review a petition to formally investigate alleged acceleration flaws in around 500,000 of the clean-energy carmaker's sedans.
The National Highway Traffic Safety Administration (NHTSA) said it will look into reports that the Tesla sedans -- ranging from the Model S, the Model X and the Model 3 -- were subject to sudden and unintended acceleration, causing as many as 100 accidents and 52 injuries over the past eight years.
Tesla shares were marked 0.35% lower in early trading Friday to indicate an opening bell price of $511.54 each.
The NHTSA defines "sudden acceleration incidents" as "unintended, unexpected, high-power accelerations from a stationary position or a very low initial speed accompanied by an apparent loss of braking effectiveness."
in 2016, a Tesla Model X crashed into a building in Irvine, California after its driver claimed the SUV accelerated on its own as he manouvered into a parking spot.
Tesla investigated the incident, using logs of the vehicles activity, and determined that the car was not in 'autopilot' mode when the accident occurred.