What is b on prius?

The "b" on the Prius refers to the "B" Mode, which stands for Brake Mode. It is a feature on Toyota Prius hybrid vehicles that allows the driver to increase the regenerative braking effect.

In the "B" Mode, when the driver releases the accelerator pedal, the vehicle's electric motor acts as a generator and converts the kinetic energy from the wheels into electric energy. This energy is then sent to the battery for storage, which helps in recharging the battery and improving overall fuel efficiency.

Typically, the "B" Mode is used when going downhill or in stop-and-go traffic, as it helps to slow down the vehicle without using the traditional brakes frequently. It essentially simulates engine braking, providing a greater level of control and reducing wear on the brake pads.

Overall, the "B" Mode is a useful feature in the Prius, allowing drivers to maximize energy recuperation and drive more efficiently.