What does warning sign O3 indicate?

The warning sign O3 indicates that there is a concealed entrance on the left, which is subsequently followed by another concealed entrance on the right. This sign is crucial for drivers as it alerts them to be cautious in these areas where other vehicles or pedestrians may be entering or exiting the roadway unexpectedly.

Recognizing this sign encourages drivers to reduce their speed and stay alert for any potential hazards that could arise from these hidden entrances. Being aware of concealed entrances helps improve overall traffic safety by preparing drivers for possible interactions with other road users who may not be immediately visible.