Which is a common error in setting up a one-lane closure?

• A. Too many flaggers
• B. High-speed traffic on the open lane
• C. Inadequate taper length
• D. Using reflective tape instead of cones

Answer: (C)

In a one-lane closure, a clear, gradual transition from the open lane into the closed lane is created by a taper. The taper length is the stretch that gives drivers enough distance to safely merge away from the closed area. If that taper is too short, drivers don’t have enough time to slow and merge smoothly, which can lead to abrupt lane changes, rear-end crashes, and back-up into the open lane. This is why inadequate taper length is a common and critical error in setting up a one-lane closure—it directly affects the safety and smooth flow of traffic through the transition. The other options aren’t as central to the setup error: too many flaggers is generally unnecessary for a standard closure, high-speed traffic on the open lane is a consequence of poor tapering rather than the setup itself, and using reflective tape instead of cones would reduce visibility and guidance but isn’t the core mistake being addressed.