Video taken on a busy road in the US appears to show a man asleep behind the wheel of a self-driving car.
The footage, which was filmed in Newton, Massachusetts on Sunday, is thought to show a driver and a passenger taking a rest from the journey in a Tesla - with their hands hanging low as the car travels along.
Neither of the pair responded to other drivers honking their horns at them.
Tesla cars, made by Elon Musk's flagship brand, boast the self-drive technology as part of their arsenal of features.
While the company has not yet responded to Sunday's reported incident, it has repeatedly warned users not to doze off whilst in control of their car.
In its user guides and safety advice, Tesla strictly maintains: "Autopilot is intended for use only with a fully attentive driver who has their hands on the wheel and is prepared to take over at any time."
It adds self-driving technology does not absolve drivers of responsibility.