What should you do when passing a row of parked cars and noticing a driver in one of the vehicles?

When passing a row of parked cars and noticing a driver in one of the vehicles, the appropriate action is to beep your horn to alert the driver. This is important because drivers may not see you approaching due to their focus inside the vehicle or on other surroundings. By using your horn, you increase the chances that the driver will become aware of your presence and may avoid opening their door into your path, thus enhancing your safety while navigating this potentially hazardous situation.

Other options may involve either speeding up, which could lead to a loss of control or an accident, or stopping unnecessarily, which could confuse both the driver and other road users. Riding too close to the parked cars could put you at risk if a door swings open unexpectedly. Using your horn serves as a proactive measure, allowing you to maintain safe speed while clearly communicating your presence.