Mournful-sounding 202 - TfL London buses, hybrid / electric sound design

This is the pulsing beacon sound emitted from speakers at the front of this bus (a 202 London TfL bus which runs between Crystal Palace and Blackheath in South East London). It's a hybrid-electric double decker bus with the diesel engine at the back and the electrical motor at the front. The bus is much quieter when under electrical power (almost silent at lower speeds) and it's a legal requirement for them to emit a sound, particularly for the benefit of blind pedestrians and passengers. There's a nice video from the company that designed them (Zelig, or just search London bus sounds), and the sound sounds great in that video. Alas in this one I think it may need to be plugged in... it sounds so sad haha. I sat at the front making this recording (I later edited out most of the door opening sounds and announcements) trying not to giggle every time it emitted another mournful sound.