ガードレールを英語でなんと言うか？

そのまんまの guardrail です。0:58 Polk County transportation division says now that they are aware of the situation it will investigate whether a guardrail is needed and will have an answer soon.

https://www.youtube.com/watch?v=8uRctPq8Bog  0:42 you're walking over Route 17 on the overpass, and there's tractor-trailers literally inches away from their bodies. there's no guardrail to protect them at all.

練習問題解答
b-1948 put guardrails on