What does a sign for an uneven road warn drivers about?

A sign indicating an uneven road serves to alert drivers that the surface they are about to encounter may be irregular or bumpy. This warning is critical as it prepares drivers for potential challenges in maintaining vehicle control, which can be particularly important in emergency response situations where speed and safety are paramount. An uneven surface can lead to loss of traction or affect vehicle stability, so being informed allows drivers to adjust their speed or driving technique accordingly to ensure a safe journey.

While the other options might suggest different conditions on the road, they do not specifically address the general state of the surface itself, which is the primary focus of the uneven road warning.