How Do Turnstiles Prevent Tailgating? Solutions for Every Security Level from Bolan Security

Structural Anti-Tailgating: Tripod and Full-Height Turnstiles

Tripod turnstiles and full-height turnstiles rely on physical structure to block tailgating at the mechanical level.

A tripod turnstile has three rotating arms spaced at 120 degrees. Only one person can pass per authorization; the arms lock immediately after each use. There is no room for a second person to slip through behind the authorized user.

Full-height turnstiles take this further with a floor-to-ceiling enclosed structure. Made of thick stainless steel, they block climbing, crawling or forced entry. The rotating barrier ensures strict one-person passage, making them ideal for high-risk areas like prisons, airports and industrial sites.

Sensor-Based Anti-Tailgating: Swing Gates, Flap Barriers and Speed Gates

For facilities needing a balance of security and accessibility, swing gates, flap barriers and speed gates use infrared sensor arrays to detect tailgating.

Multiple infrared beams are placed across the passage at different heights. When one person passes, the beams break in a normal sequence. If a second person follows too closely, the beam pattern changes, triggering an immediate alarm and locking the gate.

This method works well for medium-security sites such as office lobbies, schools and shopping malls. However, standard infrared detection has limits. It may fail to stop "piggybacking"—when two people enter together with one credential—or close following in crowded areas.

High-Security Anti-Tailgating: AB Interlocking Gates

For strict security environments like data centers, financial institutions and government buildings, standard gates are not enough. AB interlocking gates (also called mantrap gates) provide the highest level of protection.

AB gates use two linked barriers—Door A and Door B—with strict interlock logic:

· Only one door can open at a time.

· After a user authenticates (via card, face recognition or QR code), Door A opens.

· Once the user enters the intermediate zone, Door A locks.

· Infrared sensors check the zone for only one person. If clear, Door B opens.

This design eliminates basic tailgating. But a critical flaw remains: if Person A opens Door A and enters with unauthorized Person B, the system may still open Door B when A exits, leaving B inside.

Advanced Fixes for AB Gate Vulnerabilities

To solve this, Bolan Security offers two proven solutions for AB gate systems:

Dual Face Recognition Install a face recognition reader at both Door A and Door B. The system verifies the same user’s identity at both checkpoints. If Person B tries to pass without matching credentials, Door B stays locked.

3D AI Camera in Intermediate Zone Add a 3D AI depth-sensing camera between the two doors. It captures body shape, height and movement patterns to confirm the same person passes through. It distinguishes between single users and pairs, even in low light or with luggage.

These two methods ensure strict one-person-per-credential access, closing the last gap in high-security anti-tailgating.

Choose the Right Anti-Tailgating Solution

Tailgating prevention depends on your security needs:

· Basic security: Tripod turnstiles (structural protection).

· Medium security: Speed gates with infrared sensors (detection + alarm).

· High security: AB interlocking gates with dual recognition or 3D AI cameras (strict identity verification).

At Bolan Security, we customize turnstile solutions for your site—from standard tripod gates to AI-integrated AB gate systems. Our products combine durable construction, smart technology and easy integration with existing access control systems.

Ready to upgrade your access control and stop tailgating for good? Contact Bolan Security today to discuss your project. Visit www.bolansecurity.com to explore our full range of anti-tailgating turnstiles and get a free quote.