Which of these criteria is critical for turn signals during an inspection?

Turn signals play a vital role in vehicle safety as they communicate a driver's intent to other road users. For an inspection, the critical criterion is that they must function when activated. This means that when the driver operates the turn signal lever, the lights must light up and blink appropriately to indicate a turn or lane change.

This functionality ensures that other drivers and pedestrians are aware of the vehicle's movements, helping to prevent accidents on the road. Without proper functioning turn signals, there would be a significant risk of miscommunication on the road, leading to hazardous driving situations.

Other criteria mentioned do not ensure the vital safety function of the turn signals. For example, while color and appearance can play a role in visibility, they do not replace the necessity for the signals to work properly. Repairing turn signals with tape might temporarily fix a physical issue, but it does not guarantee proper operational function. Similarly, the requirement for a specific color is not as crucial as ensuring the lights function effectively to serve their purpose.