Bar gate

The boom is lowered to block vehicular or pedestrian access through a controlled point or raised to permit such traffic.

This underbar typically hangs on links, so it lies flat with the main bar as the barrier is raised.

These electromechanical devices come with 24-volt direct-current drive units which can run continuously without generating heat, so electromechanical bar gates can be operated continuously and in an intensive duty cycle.

They are also the usual method for controlling passage through toll booths,[12] and can also be found on some freeway entrance ramps which are automatically controlled to drop to restrict traffic in the event of accident cleanup or road closures without the need to dispatch road workers or law enforcement to use a vehicle to block the way.

In some places, bar gates are installed across suburban streets as a traffic calming measure, preventing through traffic, while allowing authorised vehicles such as emergency services and buses to take advantage of the shorter and more direct route.