Ob sab guardrails yog siv rau hauv nroog ntsuab qhov chaw, vaj paj txaj, chav tsev ntsuab, txoj kev, tshav dav hlau, thiab chaw nres nkoj ntsuab chaw laj kab. Cov khoom siv ob sab hlau guardrail muaj qhov zoo nkauj zoo nkauj thiab ntau xim. Lawv tsis tsuas yog ua lub luag haujlwm ntawm laj kab, tab sis kuj ua lub luag haujlwm zoo nkauj. Lub ob-sided hlau guardrail muaj ib daim phiaj yooj yim, zoo nkauj thiab siv tau; nws yooj yim rau kev thauj mus los, thiab nws cov kev teeb tsa tsis txwv los ntawm kev hloov pauv hauv av; nws yog tshwj xeeb tshaj yog adaptable rau roob, slopes, thiab multi-khoov cheeb tsam; tus nqi ntawm no hom ntawm ob sab hlau guardrail yog me ntsis qis, thiab nws yog haum rau Siv rau ib tug loj teev.