Which of the following must be functioning for a vehicle to pass inspection?

For a vehicle to pass inspection, essential safety components must be in proper working order. Headlights, brake lights, and turn signals are crucial for visibility and communication with other drivers on the road. These lights ensure that the vehicle is clearly seen, especially in low-light conditions, and help signal turning or stopping intentions, which is vital for safe driving. If any of these lighting systems are malfunctioning, it can lead to unsafe driving conditions, which is why they are mandatory items assessed during the inspection process.

In contrast, components like the radio, air freshener, and GPS system, while they may enhance the driving experience, do not directly impact the safety of the vehicle on the road. They are considered non-essential for the vehicle's operational integrity and are therefore not included in the requirements for passing a safety inspection. Focusing on the operational safety features ensures that vehicles are not only compliant with legal standards but are also safe for the driver, passengers, and other road users.