The manual which establishes the nationally recognized standards for the design and application of traffic control devices is the ______________?

The correct answer is the Manual on Uniform Traffic Control Devices. This manual is essential because it provides the nationally recognized standards for the design, installation, and maintenance of traffic control devices, which include signs, signals, and pavement markings. By standardizing these aspects of traffic management, the manual helps to ensure consistency and safety on the roads across the United States, allowing drivers to interpret traffic control devices effectively, regardless of where they are.

While other options may reference various aspects of traffic management or signage, they do not encompass the comprehensive role and acceptance of the Manual on Uniform Traffic Control Devices in establishing uniform standards related to all traffic control devices nationwide. This makes the manual not only fundamental but also legally significant in the field of traffic management.