Passengers have fled from a burning bus during morning peak hour traffic in Perth's CBD, with the vehicle completely destroyed in the blaze.
The Public Transport Authority is investigating the fire on the Mercedes diesel bus, which is believed to have begun in the airconditioning unit.
The PTA said the bus had been in service for about 15 years.
The driver was alerted to the fire when passengers smelled smoke, pulling over in Alexander Heights at 8.45am.
None of the 12 passengers who were evacuated from the bus were injured.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"The fire is unrelated to previous fires in gas buses," the PTA said.
The gas-fuelled Mercedes OC-500 model was involved in 14 fires in WA in the five years to 2013 and at least a further two this year.
