An active bolster has an expandable inner wall including a bay having first and second opposing ends and a central bowl. An expandable outer wall overlies the inner wall to provide a main cavity therebetween. An inflator is mounted within the bay having an outlet nozzle with a plurality of outlet passages for radially discharging an inflation gas against the bay and the outer wall in response to inflate the main cavity during a crash. The inner wall of the central bowl includes a plurality of first dispersion ribs substantially parallel with one another and following arcuate paths to provide at least one gas channel with opposite ends emptying from the central bowl into the main cavity. The outer wall includes a plurality of second dispersion ribs oriented to channel inflation gas from the central bowl toward the outer peripheral edges.