Driver's License Test Prep
US Road Signs Construction Signs

What does this Detour Ahead sign tell a driver about the road ahead?

Orange diamond-shaped warning sign with a black border and black text reading DETOUR 1000 FT.
  1. A.
    The road ahead is closed and traffic will follow a marked detour route. Correct
  2. B.
    One lane ahead is closed but the road stays open to through traffic.
  3. C.
    A flagger is directing traffic through the work zone ahead.
  4. D.
    Workers are on or near the shoulder in the work zone ahead.
The Why

The answer is "The road ahead is closed and traffic will follow a marked detour route."

W20-2 warns that the road ahead is closed and traffic is sent around the work zone on a marked detour, so past this point you stop navigating by memory and start reading the orange DETOUR markers. The pull toward the lane-closure answer comes from drivers who've mostly met work-zone signs that shift traffic within the same road; the detour warning is used when the through route itself is shut, not narrowed.

Why the others miss

The traps in the wrong answers

B. One lane ahead is closed but the road stays open to through traffic.

Nothing on W20-2 promises the road stays open; this device is used when the through route is closed, not narrowed. This answer treats the diamond as a lane-closure warning that leaves the roadway open to through traffic.

C. A flagger is directing traffic through the work zone ahead.

A flagger controlling traffic is announced by a separate orange diamond showing a worker holding a flag, not by this detour warning. This answer substitutes the Flagger Ahead symbol sign for the Detour Ahead warning.

D. Workers are on or near the shoulder in the work zone ahead.

The Workers Ahead diamond covers people on or near the roadway; this sign covers a closed route beyond it. This answer reaches for the crew-on-the-shoulder warning because the orange color signals a work zone.

The Rule

This question tests your knowledge of Construction Signs on the roads of every US state . Source: Manual on Uniform Traffic Control Devices, sign W20-2 (Detour Ahead)..

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