an entry control apparatus is provided . the apparatus includes a pair of spaced barriers forming a pathway therebetween . the barriers are positioned adjacent a doorway to control ingress into and egress from a building or the like . an arm is pivotally mounted and extends across the pathway and permits free movement of people in one direction and selectively restricts movement in the other direction . a motion sensor is provided and a motion control system is associated with the sensor . the sensor and motion control system cooperate to selectively allow the arms to move to a normally open position for normal traffic in an approved direction . in the event a person approaches the apparatus , as if to exit , or move in the wrong direction through the pathway , the sensor detects the movement and effects operation of the motion control system that locks the arm against movement to prevent movement through the passageway . an alarm system can be provided to alert personnel that an unauthorized movement through the pathway may be underway .