What safety feature must be inspected for functionality in all vehicles?

Windshield wipers are crucial for maintaining visibility during adverse weather conditions, such as rain or snow. Their functionality ensures that a driver can safely maintain clear sightlines, which is essential for safe driving. Inspecting the windshield wipers includes checking the blades for wear, ensuring that they make proper contact with the windshield, and verifying that the wiper motor operates correctly. In most vehicle safety regulations, such as those in Maine, operational windshield wipers are a mandated inspection point to promote overall road safety.

While the air conditioning system, sound system, and navigation system contribute to comfort and convenience, their functionality is not deemed critical to vehicle safety. Hence, they do not carry the same level of inspection priority as windshield wipers in the context of ensuring driver and passenger safety on the road.