How does barrier gates work

The family of barrier gates covers parking lot gate, tollway barrier gate, waist height turnstiles(also known as half height turnstiles), full height turnstiles, swing barrier gate, P type swing gate, retractable flap turnstiles(also known as optical turnstiles, wing barrier gate), the basic principle of barrier gate is rising the arm or unlocking the arm to let people pass through, when it is given an OPEN signal then the barrier gate will rise or unlock its arm(or boom or skirt boom or folding boom). It gives the convenience for those who need people flow under control and in order, so the barrier gates are popularly applied in many public areas, such as railway station, bus stop, subway, factory, prison, court, hospital, air port, government bureaus etc.

Barrier gates are effective way to keep public area much safer and much well-ordered.