guard rail

noun
1
a bar placed on the edge of a path, a boat, etc. to protect people and prevent them falling over the edge
نرده حفاظتی, نرده محافظ, گاردریل
2
a strong low fence or wall at the side of a road or between the two halves of a major road such as a motorway or interstate
گاردریل, نرده محافظ, نرده حفاظتی