The OSHA standard that regulates work zone safety is 29 CFR 1926 Subpart G (Signs, Signals, and Barricades) which clearly mentions that: - Construction areas shall be posted with legible traffic signs at points of hazard. - All traffic control signs or devices used for the protection of construction workers shall conform to Chapter 6 of the Manual of Uniform Traffic Control Devices (MUTCD). There are 28 OSHA-approved State Plans, operating state-wide occupational safety and health programs. State Plans are required to have standards and enforcement programs that are at least as effective as OSHA's and may have different or more stringent requirements.