Construction Zone Traffic Control (C-31) · Lesson 3 of 6

Flagger Station Placement and One-Lane, Two-Way Control

"Flagger Station Placement and One-Lane, Two-Way Control" is lesson 3 of 6 in the Construction Zone Traffic Control (C-31) Learning Hub. It opens with "The Flagger Station Must Give Drivers Room to Stop" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. The Flagger Station Must Give Drivers Room to Stop
  2. Look Up the Stopping Distance (Table 6B-2)
  3. Increase It on Downgrades (Table 6B-2(CA))
  4. One-Lane, Two-Way Control Rules
  5. Where the Flagger Stands and What to Plan

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Decide which table applies" through "Pick the flagging method".

What you'll be able to do

  • Explain the main idea of "Flagger Station Placement and One-Lane, Two-Way Control" in plain language you can use on the exam.
  • Apply this step with confidence: "Increase It on Downgrades (Table 6B-2(CA))".
  • Apply this step with confidence: "One-Lane, Two-Way Control Rules".
  • Apply this step with confidence: "Where the Flagger Stands and What to Plan".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Flagger Station Stopping DistanceONE-LANE, TWO-WAY FLAGGING, 50 MPH, SUSTAINED -6% DOWNGRADE (not to scale)WORK474 ft stopping distanceDriver sees the flagger from 474 ft (level road: 425 ft)flagger100 ft taperSTOPPING DISTANCE AT 50 MPHLevel road (Table 6B-2): 425 ft-3% 446 ft -6% 474 ft -9% 507 ft(Table 6B-2(CA); sustained, over 1 mile)-6% grade uses 474 ft474 - 425 = 49 ft more than levelONE-LANE, TWO-WAY TAPERTaper 50 ft min, 100 ft maxDevice spacing 20 ft max100 / 20 = 5 spaces5 + 1 = 6 conesFlagger at each end, one coordinatorStation needs 474 ft of stopping distance, not 425 ft100-ft one-lane, two-way taper = 6 conesSource: CA MUTCD 2026 Sections 6D.06, 6E.02, 6B.08, Tables 6B-2, 6B-2(CA), 6K-101(CA); Plan T9 Table 2CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: The Flagger Station Must Give Drivers Room to Stop

CA MUTCD 2026 Section 6D.06 says flagger stations shall be located so approaching road users have sufficient distance to stop at an intended stopping point. Except in emergencies, the station must be preceded by advance warning sign(s), and except in emergencies it must be illuminated when flagging at night (Section 6D.06, paragraph 05; Title 8 CCR Section 1599(e)). The point is simple: a flagger who cannot be seen in time, or who is placed where a loaded truck cannot stop, is the person most likely to be hit.

Step 2: Look Up the Stopping Distance (Table 6B-2)

Section 6D.06 paragraph 03 says the distances in Table 6B-2, stopping sight distance as a function of speed, may be used to locate a flagger station. On level road the table runs from 115 feet at 20 mph, 305 feet at 40 mph, 425 feet at 50 mph, 495 feet at 55 mph, up to 820 feet at 75 mph. Table 6B-2 is labeled as the suggested longitudinal buffer space length or flagger station location. Use the posted speed, the off-peak 85th-percentile speed before work started, or the anticipated operating speed.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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