Why must bridges and overpasses never be flagged?

Bridges and overpasses are unique structures that pose specific safety challenges for flaggers. The correct response highlights that these locations lack a predetermined escape route for flagging operations. In situations where flagging is necessary, it is crucial for flaggers to have a safe means of retreat in case of emergency or unforeseen circumstances. The inherent design of bridges and overpasses often restricts available space and can result in difficult or dangerous situations where flaggers might find it hard to exit quickly.

Not having a safe escape route increases the risk of accidents or harm to flaggers, as vehicles may approach more quickly than in open areas. The other options, while they may have some relevance to the safety of flaggers, do not directly address the most critical factor that makes it particularly unsafe to flag overpasses and bridges. The lack of an escape route fundamentally compromises the safety protocol that flaggers rely on in their operations.