What is used to stop a gate arm from opening when a person walks to a vehicle entry gate and presents a card?

A presence sensing entry loop is utilized to detect when a person approaches a vehicle entry gate. This technology works by creating an electromagnetic field that becomes disrupted when someone steps into it, signaling the gate system to remain closed and not open for the vehicle until the person leaves the loop area.

This is particularly important for ensuring safety and avoiding unwanted access; if a person is detected in the vicinity without an authorized vehicle, the system can prevent the gate from opening, thereby controlling access effectively.

The other options, such as an electric strike, a mechanical latch, and a photoelectric sensor, serve different functions within access control systems but do not specifically address the detection of a person approaching the gate. An electric strike controls the locking mechanism of a door, a mechanical latch secures doors or gates without electronic components, and a photoelectric sensor primarily detects light changes, typically for generating alerts rather than controlling gate access based on human presence.