What color are warning signs and what is their purpose?

Warning signs are primarily yellow with black text or symbols. Their main purpose is to alert drivers to potential hazards and changes in road conditions that may require caution. This distinctive color scheme is designed to attract attention quickly so that drivers can respond appropriately to various situations, such as curves, intersections, or construction zones.

The use of yellow for caution is a widely recognized standard that enhances visibility and communicates the need for alertness while driving. It contrasts well with other colors used for different types of signs, making it clear to the driver that they should be prepared for possible danger ahead.

Other options describe signs that serve different functions; for example, blue signs provide information about services and directions, while red signs typically indicate prohibitions or regulations requiring drivers to stop or give way. Green signs generally guide drivers towards safe routes or provide directional information, but they do not serve the hazard warning purpose that yellow signs do.