Which document provides guidelines for traffic control that must be maintained on file at each system?

The correct answer is the document that offers comprehensive guidelines for traffic control in work zones, which is vital for ensuring safe and efficient traffic management. This document outlines the procedures for setting up, maintaining, and removing traffic control devices in road work areas, addressing a variety of situations and providing standardized practices.

Having this document on file is crucial because it serves as a reference for traffic control personnel to ensure that all traffic control measures comply with established standards. It helps maintain consistency in traffic control practices across different jurisdictions and emphasizes the importance of safety for both workers and drivers.

The other parts of the Manual on Uniform Traffic Control Devices (MUTCD) focus on different aspects of traffic control, such as general standards, signs and signals, but the specific section in question directly pertains to the guidelines necessary for effective traffic control in context to work zones.