Which document's standards promote uniformity of traffic control devices across states?

• A. Federal Highway Administration Uniform Sign Standards
• B. National Cooperative Highway Research Program Guidelines
• C. Manual on Uniform Traffic Control Devices
• D. American Association of State Highway and Transportation Officials Standards

Answer: (C)

Uniformity in traffic control devices across the U.S. is achieved by the Manual on Uniform Traffic Control Devices. This federal document, published and updated by the Federal Highway Administration, sets the design, installation, placement, and usage of signs, signals, and pavement markings so drivers encounter consistent devices no matter what state they’re in. States adopt MUTCD guidelines as the baseline for their own devices, ensuring shapes, colors, sizes, lettering, and mounting practices align nationwide to reduce confusion and boost safety. Other references may cover research methods or broader standards, but they do not provide the official nationwide standard for traffic control devices.