Ib qho ntawm lub luag haujlwm tseem ceeb ntawm bollards yog los tiv thaiv tsheb-ramming tawm tsam. Los ntawm kev thaiv lossis hloov tsheb, bollards tuaj yeem tiv thaiv kev sim siv tsheb ua riam phom hauv thaj chaw muaj neeg coob lossis ze qhov chaw rhiab heev. Qhov no ua rau lawv muaj qhov tseem ceeb hauv kev tiv thaiv qhov chaw siab, xws li tsoomfwv cov tsev, tshav dav hlau, thiab cov xwm txheej tseem ceeb rau pej xeem.