Start with the lane
Measure the clear lane width and the headroom. A straight boom suits a normal lane. Folding or telescopic booms help where the ceiling is low or the arm would hit an obstruction.
Think about traffic
A quiet residential entry has very different needs from an office parking lot at shift change. Busy entries need a barrier built for frequent cycles and a fast opening time.
Add the right control
A barrier alone only lifts and lowers. Add RFID, ANPR, tickets or a keypad to decide who may enter, and loop detectors and photocells so the boom never lowers onto a vehicle.
