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Work zonesQuestion 176 of 223

A work zone device shows a steady red lens, then a flashing yellow lens. What is it doing?

  1. It is warning of a railroad crossing
  2. It is marking a school zone
  3. It is controlling traffic like a flagger
  4. It is showing a speed limit
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Correct answer: It is controlling traffic like a flagger

This is a red and yellow lens automated flagger assistance device. It alternately shows steady red and flashing yellow to control traffic.

Source: Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD), 11th Edition with Revision 1 (FHWA, December 2025), Section 6L.04 Red/Yellow Lens Automated Flagger Assistance Devices, page 869

Practice work zones

Questions last reviewed: 18 October 2026