Cov bollards uas tshem tau uas tau teeb tsa rau saum npoo av yog ib qho kev daws teeb meem kev ruaj ntseg uas tsim los muab kev tswj hwm kev nkag thiab kev tiv thaiv. Cov bollards no tau teeb tsa ruaj ntseg rau ntawm qhov chaw, ua rau lawv yooj yim tshem tawm lossis rov nruab dua thaum xav tau. Lawv muab kev sib npaug ntawm kev ruaj ntseg thiab kev yooj yim, ua rau lawv zoo tagnrho rau cov chaw uas xav tau kev tswj hwm kev nkag thiab qee zaum tso cai rau tsheb.
