Advertising agency BBDO Germany has developed a transmitter which communicates messages into passengers’ ears using "bone conduction" technology.
The technology uses the human skull to transmit vibrations to the ear, where they are then translated into sound.
BBDO chief creative officer Sebastian Hardieck said the company had received positive feedback about the ads."This experience when you put the head on the window and hear no sound waves but still hear sounds, that's very cool," he said.
But many of the comments underneath the promotional video posted to YouTube indicate otherwise.
"Suddenly one company decided to deny consumers, who already live in a world of advertisement bloated media, things like semi-peaceful naps," one comment read.
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"No thanks," read another.
Matthias Oomen, of the Public Transport Users Association, said the technology would be invasive.
"Public transport has many advantages and one of these is that you can travel in peace," he said.
Watch: The full report above.
