The road bends in the direction of the arrow, more sharply than you would guess. Often paired with a smaller advisory speed plaque underneath.
Slow before the curve, not inside it. Braking mid-curve on a fast bend is how tires lose grip; enter slow, exit smooth.
The arrow is a photograph of the next ten seconds of road.
Ignoring the small advisory speed under the diamond. That number is measured for this exact bend; the main limit is not.
Signs that live in the same family, or get confused with this one.
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