The budding trend toward battery-powered cars is unfolding as new mainstream models from General Motors, Nissan and others proliferate rapidly in the U.S. market, introducing an alternative mode of vehicle operation, which drivers accustomed to gas pedal and brake may find unfamiliar.

The accelerator of a pure electric vehicle, operated by the right foot as in a conventional vehicle, no longer qualifies as a "gas pedal"- strictly speaking – since an EV doesn't use gasoline as fuel. Instead, an EV's pedal controls the flow of electricity in two directions: to propel the car and to slow it down.Likewise, a conventional brake, operated by the left foot, that relies on friction for stopping is needed far less – and sometimes not at all – to slow the car. Instead, EVs rely in varying degrees on so-called regenerative braking. This type of braking converts the kinetic energy of a vehicle into electricity to slow the vehicle down; the electricity produced serves to recharge the battery.
But the strength of regenerative braking offered by manufacturers and the way regeneration is controlled are as varied as the different types of EVs.

Nissan's second-generation Leaf EV, debuting in the U.S. in early 2018, comes equipped with a driving mode the automaker calls "e-pedal," a surrogate for a gas pedal and one of the more powerful regenerative formats among EVs on the market. In e-pedal mode, the driver is able to drive the new Leaf most of the time with just the right foot, using the friction brake sparingly or when a sudden stop becomes necessary.

Depressing Leaf's e-pedal propels the car; as soon as pressure from the right foot is reduced, regenerative braking begins.

"We didn't offer e-pedal on the first generation Leaf because our first EV was conceived to feel more like a normal gasoline-powered car," said Owen Thunes, a manager of Nissan's powertrain technical affairs.

In Nissan's first generation Leaf, introduced at the end of 2010, lifting one's foot from the accelerator produces a relatively light regenerative braking effect, measuring about 0.03 g (g being the force of the earth's gravity). The force of the regenerative brake on the new Leaf is rated at 0.2 g or about seven times the previous model, Thunes said. In additional to the e-pedal, the new Leaf also offers two settings for a more conventional driving feel, with less regenerative braking effect.