Final answer:
On elevated lines during daylight hours, the caution signal is a yellow flag. The yellow flag is used to indicate caution or warning.
Step-by-step explanation:
On elevated lines during daylight hours, the caution signal is a yellow flag. The yellow flag is used in various contexts to indicate caution or warning, such as in sports, racing, and transportation. It is used to alert drivers and pedestrians to exercise caution and be prepared to take appropriate action.