The sign "Vehicles with water-hazardous cargo" indicates a warning for drivers about the presence of vehicles transporting materials that could be dangerous to water bodies in case of an accident. This sign is typically used near areas where traffic may affect waterways, such as near rivers, lakes, or reservoirs.

The purpose of this sign is to raise awareness among drivers that they should exercise extra caution while driving in these areas to prevent potential environmental hazards. It is advisable to drive carefully and be alert for the possibility of vehicles carrying hazardous materials, which could pose risks in the event of spills or accidents.

If you have any more questions about traffic signs or rules, feel free to ask!