it does the same thing on a straight truck, only it applies the brakes on the truck. it is used so those of us who don't have 3 legs don't have to figure out how to do one foot on the brake, one foot on the clutch, and one foot on the gas when trying to take off while on a hill. it is not---ever-for parking, even for a little bit. air pressure can, sometimes, push the lever back into the release position.
pictures of andy divine from the old wild bill hickock show yelling "wait for me wild bill" come to mind. so do pictures of dead people and wrecked trucks..................
by the way, joe has a pretty good handle on things.
