Answer: They must be flagged with highly visible materials at least every six feet
Explanation:
If wire rope guardrails are used, then they must be flagged. It is a standard practice to use highly visible material every six feet for best visibility. This is an important guideline that must be followed, so the probability of accidents can be lowered and minimized. Moreover, the Wire rope guardrails used should be capable of withstanding a weight of 200 pounds.