What are the guidelines for operating a bicycle safely?

Wearing a helmet, obeying traffic signals, and being visible to others are essential guidelines for operating a bicycle safely. Wearing a helmet significantly reduces the risk of head injuries in the event of an accident. Obeying traffic signals ensures that cyclists follow the same rules as other vehicles, which is crucial for maintaining order and safety on the roads. Being visible to others, through bright clothing or lights, helps reduce the chances of accidents, especially in low-light conditions or when sharing the road with vehicles.

The other options suggest practices that may not prioritize safety in the same way. Riding on sidewalks at all times can be unsafe due to pedestrian traffic and may even be illegal in certain areas. Limiting riding to daylight hours and low-traffic areas ignores the importance of being prepared to ride safely at any time, and busy road avoidance doesn't address overall traffic behavior and laws. Using bicycle gears frequently may enhance riding efficiency but does not directly contribute to safety in the same manner as adhering to traffic laws.