Curve Ahead Sign
The curve ahead sign warns drivers of a gradual curve in the road ahead. Drivers should reduce speed before entering the curve, not during it, to maintain control and stay in their lane.
Last updated: April 4, 2026
The curve ahead sign alerts drivers to a change in the road alignment ahead. The sign shows the approximate shape of the curve. A gradual curve uses a gentle arrow, while a sharp curve uses a tighter angle. The speed advisory panel below the diamond sign, if present, shows the recommended safe speed for the curve, which is lower than the posted limit.
Quick Facts
Type
Warning Sign
Shape
Diamond
Colours
Yellow background with black curved arrow
In this guide
What does the Curve Ahead Sign mean?
The curve ahead sign alerts drivers to a change in the road alignment ahead. The sign shows the approximate shape of the curve. A gradual curve uses a gentle arrow, while a sharp curve uses a tighter angle. The speed advisory panel below the diamond sign, if present, shows the recommended safe speed for the curve, which is lower than the posted limit.
What to do when you see it
Begin reducing speed before the curve begins. Do not brake sharply inside a curve, which can cause skidding. Maintain a steady speed through the curve and keep to the right of the centre line. Look ahead through the curve to anticipate road conditions. On wet or icy roads, slow further below any advisory speed.
Where you'll see it in Ontario
Curve ahead signs are found on rural roads, highways, and urban arterials where the road changes direction. They appear far enough in advance to give drivers time to slow down before entering the curve. In Ontario, they are especially common on roads through the Oak Ridges Moraine and other hilly terrain.
G1 test relevance
G1 questions on warning signs frequently include the curve ahead sign because it is one of the most common diamond-shaped signs. Candidates should know the shape, colour, and the correct driving response, which is to slow before, not during, the curve.
Common mistakes drivers make
Entering the curve at the full posted speed and braking inside the curve is the most common and dangerous error. If the vehicle understeers or oversteers, the driver may cross into oncoming traffic or leave the road.
Related Signs
Sharp Curve Sign
The sharp curve sign warns of a severe change in road direction that requires a significant reduction in speed. It is more urgent than the standard curve ahead sign and often accompanied by a speed advisory panel.
Learn moreWinding Road Sign
The winding road sign warns of a series of three or more curves or bends in the road ahead. Drivers should reduce speed and maintain a steady pace through the entire winding section, not just the first curve.
Learn moreSteep Hill Downward Sign
The steep hill downward sign warns of a significant downgrade ahead. Drivers must select an appropriate gear before descending to avoid brake fade, especially in heavy vehicles.
Learn moreSlippery When Wet Sign
The slippery when wet sign warns that the road surface loses traction significantly in wet conditions. Drivers must reduce speed below the normal limit when the road is wet, icy, or covered in leaves.
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