Which revolutionary feature was first introduced in BYD's K9 electric bus in 2010, setting a new standard for the industry?

Public transportation is rapidly evolving with electric buses becoming a cornerstone of sustainable urban mobility. These vehicles represent a significant innovation in transportation product design, combining environmental benefits with technological advancement. This trivia question focuses on a breakthrough moment in electric bus development that changed the industry's trajectory. Test your knowledge of transportation product innovation!

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Iron-phosphate battery technology that eliminated the need for overnight charging
Regenerative braking system that recovered 70% of kinetic energy
Solar panel roof integration that extended range by 15%
Wireless induction charging capability at bus stops