What is bird cage construction in commercial buses?

Bird cage construction in commercial buses refers to a construction style where the entire frame is integrated into one cohesive unit. This method enhances the structural integrity and safety of the bus, allowing for better performance during collisions and other stresses that the vehicle might face. The term "bird cage" reflects the way the frame supports the overall body, much like how a bird cage holds together its components. This kind of construction is beneficial in maintaining the shape and durability of the bus while also simplifying the manufacturing process.

In contrast, the options related to lightweight body creation, soundproofing techniques, or designs that involve multiple separate sections do not accurately describe the fundamental characteristic of bird cage construction, which emphasizes a singular, unified frame for strength and stability.