crash barrier
noun (British English)(North American English guard rail)
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 （高速公路或州际公路上的）防撞护栏，防撞墙 Crash barriers were erected along the roads to be used for the race. 沿路建起了防撞护栏，以备赛车之用。