| 摘要 |
A portable traffic control device having a housing, two generally parallel and independently rotatable shafts beyond extending the housing length, and a plurality of blades connected to each shaft. Each shaft rotates such that the blades on that shaft either protrude up through openings in the top of the housing or extend horizontally within the housing. When a shaft is rotated such that its blades protrude upward, the blades remain protruding and puncture the tires of vehicles driving over the housing in a first direction. The blades are pushed downward into the housing by contact with tires of vehicles driving over the housing in the opposite direction. Biasing means rotates that shaft pushing the blades up to their protruding position. The device is modular in that two or more devices may be detachably connected in series wherein all of the first shafts and all of the second shafts rotate in unison.
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