Warning signs
Reverse Curve sign
The road bends one way and then immediately the opposite way, forming an S shape. Slow down before the first bend and hold a steady line through both.
- Diamond
- Yellow
- MUTCD W1-4
Shape and background first
Federal designation W1-4 in the MUTCD, the national standard every state signs to. Common on roads crossing rolling terrain or hugging a riverbank, where the route has to double back through two connected bends in short succession.
What the MUTCD specifies
Designation: W1-4
MUTCD Section 2C.07
Conventional road size: 30 x 30 in
Source: Federal Highway Administration, MUTCD 11th Edition (December 2023), Part 2, Table 2C-1, verified 2026-09-26.
What the test wants you to know
The mistake people make
Drivers who brake mid curve rather than before it are the ones who lose traction on a reverse curve, because the direction change leaves no straight recovery section between the two bends. Test questions on this sign usually ask when to slow, and the answer is always before you enter, not partway through.
The sign people confuse it with
Reverse Curve gets mixed up with Winding Road more than any other pairing in this category. Put them side by side and the difference is obvious, which is exactly why it is worth doing once rather than meeting them cold in the exam.
Reverse Curve
The road bends one way and then immediately the opposite way, forming an S shape.
Winding Road
A series of three or more curves lies ahead, alternating direction over a longer stretch.
