A one-way turnstile is a turnstile that only allows pedestrian access in one direction. One-way access is one of two turnstile configurations, with the other being two-way, or bi-directional access. One-way turnstiles are great for both crowd control and security.
One-way turnstiles are used to restrict the flow of traffic through an area to one direction. They are commonly used at amusement parks, stadiums, subways stations, and at construction sites, warehouses and distribution centers. More specifically, stadiums and amusement parks use them at exits to ensure that patrons do not sneak back in.