When the objective is to monitor the movement of vehicles, you need a boom barrier that is a horizontal bar with vertical movement. Space saving is the biggest advantage of this security equipment that needs only a machine to move the bar up and down to control vehicular movement in parking facilities, level crossings and drawbridges.
For long, boom barriers were used to be hand operated – the bar rests on a pole with a weight tied at the pole end and a rope for movement at the other. The rope is pulled down for closing movement and let free for the opening. Today the weight is replaced with a 24VDC drive unit that moves the bar up and down with little supervision.