When are clearance lights required by state law for trucks or buses?

Answer: A — If the width is 80 inches or more

Clearance lights are required for trucks or buses when their width is 80 inches or more. This requirement is in place to ensure that larger vehicles are visible to other road users, particularly at night or in low-visibility conditions. The lights help delineate the vehicle's outer edges, providing an additional safety measure. While height, weight, and length might also influence other lighting requirements, the specific regulation regarding clearance lights focuses on the width of the vehicle. Width is a critical factor because vehicles wider than 80 inches can pose a visibility hazard, and having appropriate lights ensures that they are seen clearly and can navigate safely in traffic.