| 摘要 |
A bollard type trafficway barrier for arresting vehicles, comprised of a cast in place foundation and a bollard replaceable therein with a spring for lifting the bollard that is directionally oriented with respect to traffic so as to withstand great impacts, and with access for replacement of the bollard, with retraction by manual depression and extension by instantaneous release of potential energy stored in said spring, the bollard being locked in both the retracted and extended conditions, and installation being flush with the grade when retracted and the bollard being released manually or power controlled from a remote location by a vehicle sensor.
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