US Patent 7314020 Over-height vehicle barriers

An over-height vehicle barrier has a supporting beam mounted above a carriageway, with multiple blade-like members rotatably mounted to the supporting beam such that the blade-like members are suspended downwardly from the beam in parallel relationship and in close proximity one to another. A leading edge of each member faces oncoming traffic on the carriageway for possible engagement by an over-height vehicle such that each member can rotate about the axis of the beam independently of the other members when struck by an over-height vehicle. A further beam is engageable by the rotating members when struck by a vehicle to limit the extent of rotation about the axis of the beam and to thereby cause the members to rotate in a return direction. Engagement of the members by a vehicle generates a warning noise to alert the driver of the vehicle and the further beam itself can generate further additional noise when engaged by the rotating members.