What defines a roadblock?

A roadblock is specifically characterized by the use of vehicles, barricades, or cones to effectively block or redirect traffic flow. This is typically set up to control access to certain areas, either for safety reasons—such as construction, accident response, or event management—or for legal enforcement, like public safety checkpoints. The physical barriers designed to obstruct or redirect traffic are essential elements of a roadblock, ensuring that vehicles cannot proceed through that specific area.

Other options describe activities related to traffic management but do not capture the essence of a roadblock. For example, random placement of warning signs is more about alerting drivers to potential hazards rather than blocking access. The temporary closure of a lane may involve roadblocks but does not depict a full roadblock scenario that effectively blocks access. A legal checkpoint focuses on inspecting vehicles but not on impeding traffic flow in the same manner as a roadblock.