A locking device is provided for preventing a motor vehicle door from opening when a handle portion of a handle assembly moves with acceleration above a predetermined threshold relative to a base thereof. The locking device includes a lock cup fixedly secured to the base and having a plurality of teeth. The locking device also includes a spool rotatably coupled to the lock cup and operably connected to the handle portion. The spool includes a pawl rotatably mounted thereto. The locking device further includes an inertia element disposed between the lock cup and the spool. The inertia element is coupled to the pawl such that upon the acceleration above the predetermined threshold the inertia element lags rotation of the spool and forces the pawl into engagement with one of the plurality of teeth to stop movement of the handle portion relative to the base and prevent the door from opening.