What must be checked regarding the turn signals installed in vehicles?

Turn signals are essential components of vehicle safety, designed to indicate a driver's intentions to other road users. Ensuring that these signals meet specific intensity and size requirements is crucial for visibility and effectiveness. Adequate intensity ensures that turn signals are bright enough to be seen in various lighting conditions, including bright daylight, which can be particularly challenging. Size requirements help ensure that the signals are noticeable from a distance, allowing other drivers and pedestrians to react appropriately.

Meeting these standards not only enhances road safety but also ensures compliance with legal regulations governing vehicle equipment. This is why the correct answer emphasizes the importance of these specifications—safety on the road hinges on all drivers being able to communicate their intentions clearly, and properly functioning turn signals are vital to this communication.