Alternate reality
"Is the parking brake on?"
In the alternate reality, the external inertial dampener was the technological equivalent to a parking brake, found aboard Constitution-class starships. When engaged, such technology prevented a starship from jumping to warp.
In 2258, prior to his first jump to warp as helmsman aboard the USS Enterprise, a nervous Hikaru Sulu failed to disengage the external inertial dampeners until Spock advised him. (Star Trek)
The external inertial dampener from the film Star Trek was described as a "field-manipulation device designed to compensate for gravitational or acceleration forces when a starship is in dock" by the Star Trek Encyclopedia, 4th ed., vol. 1, p. 256.