Elon Musk took to Twitter last night to say that the latest Full Self-Driving (FSD) Beta version 9.2 is "actually not great imo, but Autopilot/AI team is rallying to improve as fast as possible."

"We're trying to have a single stack for both highway & city streets, but it requires massive NN (neural network) retraining,” he added in a tweet.

His tweet comes just days after Tesla’s AI day after he heaped praise on Tesla’s AI capabilities. The EV maker plans to further upgrade its FSD system to allow for automatic steering on city streets.

Last week, the National Highway Transportation Safety Administration (NHTSA) opened an investigation about car accidents that involved Tesla cars. Accordingly, at least seven accidents resulted in 17 injuries and one death.

"NHTSA reminds the public that no commercially available motor vehicles today are capable of driving themselves," said the agency in a statement.

"Every available vehicle requires a human driver to be in control at all times, and all state laws hold human drivers responsible for operation of their vehicles. Certain advanced driving assistance features can promote safety by helping drivers avoid crashes and mitigate the severity of crashes that occur, but as with all technologies and equipment on motor vehicles, drivers must use them correctly and responsibly."

Tesla sells FSD for $10,000 or $199 per month in the US. The system is still described as a “premium driver assistance” with the driver still required to sit behind the wheel.