The pedals of a car, are an important interface for the interaction between the driver and the car. The accelerator – brake – clutch arrangement caught on in the 1920s. The emergence of the automatic transmission made left-foot operation obsolet.
Concerted efforts: Driving a car requires coordinated actions. The most important of those are accelerating, steering, indicating the turning direction, braking, shifting and operating the clutch – and, of course, observing traffic while doing so. Early inventors quickly agreed that, in addition to the hands, the feet would also be used to operate the automotive mobility machine. Vehicles were given pedals.
Standardisation: At the start, however, there was no consensus on where the driver was supposed to step. Each vehicle manufacturer had a different arrangement of the accelerator, brake and clutch. The Prussian military clarified the situation. In 1908, the pedal arrangement was standardised in army vehicles so that drivers could easily handle cars of different makes.
Uniformity: This is how the arrangement of the accelerator, brake and clutch (from right to left), which is still used to this day, emerged in German Imperial army trucks. It did not immediately catch on everywhere, however. Up into the 1920s, the number and arrangement of pedals in cars was anything but uniform. The accelerator was often located in the middle. This was also the case in racing cars. Little by little, however, the current standard won out.
Clarity: The three pedals of the “33 Extras” at the Mercedes-Benz Museum demonstrate an exceptional ease of operation. Cast letters clearly label the assigned functions of the clutch and brake. At the same time, this step plate design also prevents shoes from slipping.
Transition: It was common for the right foot to operate the accelerator and brake and for the left foot to step on the clutch pedal. Automatic transmissions became more widespread starting in the 1950s, leaving only an accelerator and a brake pedal. That is the future: manual transmissions were taken out of the Mercedes-Benz range little by little; electric vehicles also generally have just the two pedals. This means that left-foot operation became obsolete.
Locked: For Mercedes-Benz, this is not the whole story. Over the decades, vehicles from the manufacturer have had another pedal on the far left in the footwell for actuating the parking brake, instead of a handbrake lever. It is released using a handle on the left underneath the steering wheel.
“Gas”: The accelerator is called the gas pedal because it is used to regulate the volume of the gas/air mixture that enters the combustion engine. Low for little power development, and a lot when more is desired. Even in electric cars, the right pedal is commonly called the gas pedal, despite controlling the flow of electrical energy instead of the output of chemical energy in the form of fuel.
Accessible: What if the driver has a physical disability that makes it impossible to use the standard pedals? Mercedes-Benz offers driving aids from the factory, including pedal adaptations and pedal covers.
No pedals: Modern Mercedes-Benz vehicles already offer countless assistance systems that take over pedal-operated functions – such as DISTRONIC Active Distance Assist. If a fully automated driving mode is available for certain routes in the future, the pedal could be completely retracted in this situation to increase comfort. This has been demonstrated in the 2019 Mercedes-Benz Experimental Safety Vehicle (ESF).
Rally sport: In very sporty driving, some racers prefer heel-and-toe shifting. This makes it possible to brake while simultaneously downshifting. In this process, the toe of the right foot operates the brake pedal, while the heel taps the throttle.
Source: Mercedes-Benz Museum