What is the rule regarding wearing headphones while driving?

Wearing headphones while driving is generally regulated because they can impede a driver's ability to hear important sounds in the environment, such as horns, sirens, or other vehicles. The rule that allows the use of headphones in one ear specifically aims to strike a balance between enjoying music or directions while still being aware of surrounding sounds that are essential for safe driving. This allows the driver to maintain some auditory awareness of the road while potentially benefiting from navigation assistance or music. Using headphones in both ears would isolate the driver from critical auditory cues, increasing the risk of an accident, which is why that practice is typically not permitted.