Maya Wirz's performance was posted on YouTube.com.
Wirz has spent 13 years behind the wheel. She said she was tired of driving and wanted to sing, so she did.
The 49-year-old practiced her pipes on the bus once everyone got off.
At the urging of her boss, Wirz recently appeared on the televised talent show and received a standing ovation.
She is now being called Switzerland's Susan Boyle.