The system uses an electric motor to generate resistance to a driver's speed impulse, shifting the “bite point” of the pedal – and can be programmed to react to different degrees of pressure.
There is even the option to make the accelerator vibrate against or tap the driver's right foot to remind them to lay off the gas, news magazine Der Spiegel reported on Tuesday.
The smart pedal would not give the driver such signals when pulling away from a traffic light or accelerating onto a motorway. Currently it reacts to information from the car's navigation system, and the sensors on the front and back which monitor how close the next vehicle or obstacle is.
But this could be expanded to include information about approaching road junctions or speed limits, Benjamin Lippert, Mercedes development engineer told the magazine.
When approaching a turning, or driveway entrance, a gentle tapping of the smart accelerator could warn the driver to slow down, while the pedal could make it more difficult for the driver to speed into a village.
“This [bite] point would be figured out for every situation, so that one accelerates as efficiently as possible,” Lippert said.
And of course, if the driver really wanted to go fast, despite the fuel consumption, they could do simply by ignoring the complaining pedal and pushing past the resistance.
But the dozens of test drivers Lippert has invited behind the wheel of his S-class for experimental trips over the past four years, all show one thing – an average reduction of fuel consumption of around 10 percent, he said.