What type of warning do posted speed limit signs with a yellow background indicate?

Posted speed limit signs featuring a yellow background are classified as cautionary signs. These signs are used to alert drivers to potential hazards or changes in road conditions that require them to adjust their speed accordingly. The use of a yellow background signifies to drivers that they should exercise caution in the area ahead because conditions may not be ideal for travel at normal speeds.

Cautionary speed limit signs are often found in areas where there may be increased risks, such as near construction zones, curves, or pedestrian crossings. While these signs indicate that drivers should be cautious, they do not carry the same enforceability or mandatory requirements as other signs, such as those with a regulatory purpose, which typically would use a white background. Understanding this distinction helps drivers recognize when they need to be particularly vigilant and prepared to slow down in response to changing conditions.