| 摘要 |
<p>The stop prevents vehicles from travelling in the wrong direction down roads and comprises a frame which is buried into the road surface. A series of spring-biassed cams are pivoted to the frame and project out of the frame when in use. The cams are shaped so that a vehicle passing in one direction momentarily depresses the cams into the frame whilst a vehicle passing in the other direction produces a resultant force on each cam which ensures that the cams continue to project out of the frame, preventing passage of the vehicle.</p> |
