A curve ahead sign means the road bends just ahead and you should slow down before you reach it. Our Curve sign (W1-2) is the yellow diamond with a curved arrow, posted in advance of the bend. React by braking on the straight approach, being at any posted advisory speed before the curve starts, holding steady through it, and looking toward the exit - not by braking mid-curve, which is what unsettles a vehicle.
A Curve sign (W1-2) with a gently curved arrow is used where the advisory speed is above 30 mph. A Turn sign (W1-1) with a right-angle arrow is used for a sharper bend, where the advisory speed is 30 mph or lower. The sharper the turn, the more abrupt the arrow.
The speed on a W13-1 plaque comes from a ball-bank engineering study of the actual curve - an instrument measures the lateral force a vehicle experiences at various speeds, and the safe number is read off that, then rounded to a 5 mph increment. You'll want one whenever the safe curve speed is well below the road's posted limit. See the combination on our supplemental curve signs.
Place a curve sign in advance of the bend, not at it, so drivers can slow in time. MUTCD Table 2C-4 sets the exact distance by approach speed - closer on a slow street, several hundred feet out on a fast highway. On a sharp or blind curve, add chevron signs (W1-8) through the bend itself for continuous guidance.
For mountain passes and canyon roads, we recommend layering the warnings: a Curve or Turn sign with an advisory speed plaque on the approach, then chevrons through the bend, since these roads combine sharp curves with limited sight distance. For a true switchback, the Hairpin Curve sign (W1-11) warns of the near-180-degree turn.
A Reverse Curve sign (W1-4) warns of two curves in opposite directions - a bend one way, then back the other. A Winding Road sign (W1-5) warns of three or more curves in a row. Two bends is a reverse curve; three or more is a winding road.
The number of arrows shows how many through lanes are being shifted. One arrow is a single lane; the double and triple reverse curve signs mark two and three lanes shifting through the curve. Match the arrow count to the number of lanes on your road.
Our standard curve signs comply with MUTCD standards, noted on each product page, since most state manuals follow the federal MUTCD - check local rules to be sure. You can also personalize text versions like the Slow Down Sharp Curve Ahead sign. For a custom design or a bulk order, call our sales team at 888-343-3771 (Mon-Fri, 8am-7pm EST) or email customerservice@smartsign.com.
We make curve ahead signs (MUTCD W1-2): our yellow diamond warning signs that tell drivers a bend is coming while there's still room to slow down. A curve ahead sign is a primary type of horizontal alignment warning sign - it notifies drivers of a change in the road's physical path, going up in advance of the curve rather than at it. That early warning helps keep a vehicle from carrying too much speed into the bend, where run-off-road crashes happen.
Choosing a Size (If/Then)
For curve signs, we recommend sizing to the road's speed, because a faster driver needs to read the sign from farther away.
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