B means Brake mode that some styles, like electrical vehicles, present. You may use it to decelerate or sustain downhill velocity without the need of using the automobile’s brakes. Automatic transmission automobiles adjust gear based upon the RPMs, so the vehicle needs to keep up superior RPMs in hilly regions. https://gearboxauto87918.bloggosite.com/40678029/details-fiction-and-gearbox-auto