A mystery fire on an abandoned bus held up motorists at the Bicester Road, Woodham, on Tuesday morning.
Bucks Fire and Rescue were called to the fire at 8.14am at the A41.
Spokesman Fraser Pearson said: “There was some suggestion it had broken down then caught fire.
“When we got there it was going rather well, as they say.”
Stu Johnston wrote on Twitter that the bus was beige and without company markings.
Did you see the bus? Do you know who owns it? Email firstname.lastname@example.org