The roadway ahead curves to the left. Slow your speed and keep well to the right.
The sign may be accompanied by an advisory speed placard, helping you navigate the curve safely. Remember that the speed specified on the placard is safe only under ideal conditions. If the road is covered in ice, snow or water, reduce speed even further.
Remember, you should brake in advance and enter the curve at safe speed. Braking through the curve may lead to losing control over the vehicle.