Earlier this month, Tesla Motors CEO Elon Musk tweeted that he would on 17 October reveal a new product that was "unexpected by most"; over the weekend, however, Mr. Musk said the announcement would be delayed for two days until Wednesday because the mystery gadget needed "a few more days of refinement".

There has been quite a bit of speculation about what is going to be unveiled.  The tech journal Recode speculates that Mr. Musk was planning to introduce a new version of the company's at-home energy storage devices called the Powerwall and the Powerpack.  That had already been promised before the end of 2017.  Another possibility is that Tesla will launch an updated version of the company's semi-autonomous driving system called Autopilot 2.0.

That would be a timely improvement, as Germany over the weekend asked Tesla to stop advertising its electric vehicles as having an "Autopilot" function.  Transport Minister Alexander Dobrindt says that name "Autopilot" suggests that the drivers' attention is not needed at the controls of a Tesla vehicle.  But there have been a collisions involving people who became convinced they could rely completely on Autopilot to drive their vehicles, not least of which was a man who was decapitated in Florida when his Tesla Model S on Autopilot drove underneath a truck.  Police later determined he was speeding.

Germany's Federal Motor Transport Authority wrote to Tesla:  "In order to prevent misunderstanding and incorrect customers' expectations, we demand that the misleading term Autopilot is no longer used in advertising the system."

But Tesla insists it had always made it clear to customers that they must pay attention at all times when behind the wheel of a car, even if the assistance system was engaged.  "Just as in an airplane, when used properly, Autopilot reduces driver workload and provides an added layer of safety when compared to purely manual driving," said a Tesla spokeswoman.