What does this traffic sign indicate?

You answered correctly. This triangular warning sign with a rider on a horse alerts drivers to be cautious because horses may be on or crossing the road. It warns of possible danger and signals that you should reduce speed and be ready to react calmly, as horses can be unpredictable. The sign does not give priority to people on horseback, nor does it mean the road is only for horses. Recognize this sign as a general warning to drive carefully wherever horse riders may be present.