Transit officials have yet to determine the cause of a fire on this busy Saturday afternoon. ((Submitted by Ruby Benson))

Edmonton transit officials are trying to determine what caused a fire on a public transit bus on Saturday afternoon.

The driver was alerted to the fire when smoke started coming out of the engine.

Ruby Benson was driving along 118th Avenue when smoke suddenly clouded her view.

"Traffic was all backed up and you could barely see the car in front of you, and then we got close up and we finally seen it was one of those bendy buses and the back end of it was all on fire," she said.

All of the passengers got off the bus without injury.

Damage is estimated at $30,000.