What does a triangular road sign bearing the picture of a horse warn drivers about?

A triangular road sign featuring a picture of a horse primarily indicates a warning regarding the presence of horse-drawn vehicles. This type of sign serves to alert drivers to be vigilant for horses, which may be on the road or on adjacent paths, particularly in rural areas.

The purpose of this warning is to enhance safety, as horse-drawn vehicles can be slower and may require more space than motor vehicles. Additionally, it reminds drivers to take care as real horses can be sensitive and unpredictable, especially if they are near the roadway.

Other options, while related to horses, do not accurately depict the specific warning that the triangular sign provides. For instance, accompanied horses could suggest a different situation where horses are being ridden or handled on the road, which may not necessarily involve drawn vehicles. Similarly, horse racing events and farm machinery involve different contexts and signage, making them unrelated to the sign that specifically indicates caution for horse-drawn vehicles.