The concept is easy enough: push the pedal further to go faster and ease off of the pedal to go slower.
Going faster uses a burst of energy to accelerate to a higher speed. Going slower uses the motor as a generator to capture energy and put it back in the battery. If a particular car model could regenerate energy like this with enough deceleration force then it was considered to have “one pedal driving”.
Tesla cars with their large and powerful battery packs and motors can do this during typical daily driving. However, a car like the original Nissan LEAF which had a smaller battery with modest regenerative capability tended to require more use of the dedicated brake pedal and many wouldn’t consider it to have one pedal capability.
Other cars offered a middle ground. A Chevrolet Volt plug-in hybrid when driven in its enhanced regenerative ‘L’ drive setting could be driven mostly in a one pedal style but only in a relatively sedate driving style.
Even in a Tesla, the regenerative effect fades into a glide as the vehicle speed drops below around 5 miles per hour. This means the brake pedal must still be used to bring the car to a full stop.
One pedal driving changed when BMW delivered their new i3 electric car in 2014. The i3 powertrain was designed to not only regeneratively slow down while driving but also to smoothly bring the car to a full stop without requiring the use of the brake pedal. It could also stop and hold itself on a mildly inclined road. On a downhill road the regen slows the car to a crawl but allows the car to slip a bit in the forward direction and the brake pedal needs to be used to completely stop and hold the vehicle. Some owners say earlier model years of the i3 had stronger regeneration and that it was softened by BMW later.
Next, the 2017 Chevrolet Bolt adopted a similar approach but with somewhat stronger regenerative force and the ability to stop and hold on slightly more inclined roads without use of the brake pedal when driven with its shifter in the ‘L’ position. In the Bolt’s normal ‘D’ drive mode it emulates a typical automatic transmission gasoline car in that it automatically creeps forward at a slow speed if you don’t have your foot on the brake pedal. The BMW i3 is always in the equivalent of the Bolt’s ‘L’ mode.
The Bolt EV can regeneratively brake even stronger still if the driver also uses a paddle on the left back side of the steering wheel. When pressed, this enhances the regenerative braking effect but the overall strength is still controlled with the driver’s foot on the ‘go’ pedal.
Now, the 2018 Nissan LEAF has introduced what Nissan calls an “e-Pedal” driving mode which adds automatic use of the hydraulic friction brakes and can hold the car on even steep hills heading either up or down, according to Nissan.
The new LEAF e-pedal has a modest regenerative braking effect at highway speeds but as it slows it feels stronger and brakes to a complete stop, maybe even a bit too aggressively, if you completely let off of the ‘go’ pedal. It is enable by a dedicated e-Pedal mode switch on the dashboard.
The i3, Bolt, and 2018 LEAF have a qualitatively different, and better, one pedal implementation than a Tesla or other EVs that don’t quickly come to a full stop by themselves.
This distinctive ability probably needs a unique name brand-neutral name other than just “one pedal driving”.