| 摘要 |
<p>A blocking element (21) for use in a device for selectively allowing and preventing the passage of one or more vehicles along a pathway, the blocking element comprising: a framework supporting at least one frangible blocking face (23) facing the intended direction from which a collision might occur, the face and the frame forming a cavity (30) behind the face; and an engagement element (28) mounted in the cavity behind the blocking face, whereby, when the frangible blocking face is broken upon impact with a vehicle, the engagement element is revealed and is arranged to engage the tyres of the vehicle involved in the collision, thereby preventing the vehicle reiding over the blocking element.</p> |
