An "unattended" bus crashed on a busy Cardiff road on Saturday, leaving the road closed to motorists for hours.
South Wales Police said they were called to reports of a bus with nobody inside it on Saturday.
Pictures from the scene show the damaged rear of the bus after it appears to have crashed into metal railings.
Heol Pontprennau was closed after the crash, between the A4232 and Heol Glaslyn, which caused delays to motorists in the area.
Debris could be seen across the road after the bus came to a stop at an angle.
A police spokeswoman said: "We were called at 11.25am to the Cardiff Gate Retail Park to reports of an unattended bus in collision with traffic lights."
Nobody was injured in the collision, and the road was closed in both directions for around three hours while the bus was being recovered.
Cardiff Bus say an investigation is ongoing.
Cardiff Bus tweeted about a "high level" of congestion in the Asda Pontprennau area due to a crash.
Kath Jones was driving to Asda and described "very heavy traffic" in the area.
Kath, 36, from St Mellons, described seeing the damaged bus on the busy road with police cars at the scene.
She said: "I was leaving my mum and dad's and was going to go to Asda, and the traffic was really, really heavy."
A spokesperson for Cardiff Bus said: "We are dealing with an incident with one of our buses.
"An investigation is ongoing to determine what happened and we are working with the police."
The spokesperson added the cause of the crash has not yet been determined, but that a "number of eyewitnesses" have suggested nobody was inside the bus at the time of the crash.
Cardiff Bus asked passengers to allow extra time to travel and apologised for any inconvenience caused.
