Mantraps are designed to prevent tailgating by ensuring that only one person can enter or exit an area after authentication. They are typically structured as two sets of interlocking doors that only allow one door to be open at once, thus preventing an unauthorized person from following an authorized person into a secure area. Turnstiles, while useful for controlling flow, can still be susceptible to tailgating, especially if they are not full-height. Biometric systems strengthen the authentication process but do not, on their own, prevent tailgating. Surveillance cameras can record attempts at tailgating but do not actively prevent the act.