Night Work Zone: Flagger, Portable Signal, and Pilot Car
At 11:20 p.m. you are northbound on I-25 in Colorado and enter a night work zone. Orange signs read 'LEFT LANE CLOSED AHEAD' and 'REDUCED SPEED AHEAD'; a portable changeable message sign shows 'SPEED LIMIT 45.' The permanent limit is 65 mph. A flagger ahead holds a STOP/SLOW paddle, but the paddle is turned edge-on and is hard to read. A portable traffic signal shows green. A pilot car with flashing yellow lights waits on the right shoulder. The lane taper uses orange drums, and a temporary yellow line shifts traffic to the right. You are in the left lane at 60 mph, with a concrete barrier about four feet to your left. The flagger suddenly rotates the paddle to STOP while your front bumper is at the start of the taper. A semi is close behind you.
1. What speed and lane position should you choose on entering the taper, and why?
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You should reduce speed before the taper so that you are at or below the posted 45 mph work-zone limit when you reach the drums, and you should move right promptly and smoothly because the left lane is closing. The 45 mph panel is a regulatory speed limit for the work zone, not an advisory speed; the permanent 65 mph limit does not override it. Your left-side barrier removes the shoulder as an escape path, so a late, fast merge is especially risky. The semi close behind is a reason to signal early and brake progressively, not a reason to carry 60 mph into the taper. Work-zone lane shifts marked by a temporary yellow line should be followed rather than treated as optional, and you should not use the closed lane to gain position. The correct sequence is slow first, merge right, then establish a safe following distance.
2. The portable signal is green, but the flagger turns the paddle to STOP. Which control governs, and what should you do?
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A flagger's direction governs over the portable signal. The green light does not authorize you to proceed against a STOP paddle. Because your front bumper is only at the start of the taper and the flagger is ahead, you should come to a controlled stop before the flagger's position, using the space in the taper rather than stopping on the traveled through lane if you can avoid it. Check the mirror and brake early enough to give the semi behind you warning; a sudden panic stop is more dangerous than a firm, progressive stop. Do not back up and do not drive around the flagger. If you are already past the flagger when the paddle changes, continue through the work area as directed rather than stopping in a hazardous location. The key judgment is that the flagger controls the movement, and the signal is secondary.
3. What should you do about the pilot car and the temporary yellow line?
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The pilot car indicates that traffic is being escorted through the work zone. You should wait for the flagger's signal to proceed, then follow the pilot car at a safe distance; you do not pass it or try to keep up aggressively. The temporary yellow line marks the shifted alignment through the taper and work area, so treat it as the lane boundary and do not cross it to regain the closed lane or to overtake. The high-visibility pilot car also gives you a cue about the path through the drums, but it does not authorize ignoring the flagger or the posted speed. If the pilot car moves out and the flagger still shows STOP, you remain stopped. The judgment is to follow the human control and the temporary markings together, not to treat the green signal or the pilot car's lights as independent permission to go.