A four-year-old girl was taken to hospital after a large stone smashed through a car's windscreen and hit her in the face.
It happened while she was travelling in a BMW on the M5 on Sunday (23 October).
Several large pieces of stone had fallen onto the road and one of these was thrown into the air by a vehicle.
It then smacked into the passenger windscreen of the BMW 3 series and struck the child in the face.
She was taken to Worcester Hospital and received treatment for facial injuries and bruising.
Detectives from Gloucestershire Police are now appealing for witnesses to come forward.
PC John Baldwin from the Roads Policing Unit said: “We are interested in hearing from any motorists who were travelling northbound on the M5 towards junction eight at around 4pm on that Sunday who may have seen the stone debris falling off a vehicle.
"We are also keen to hear from anyone who may have dashcam footage of the incident.”
Anyone with information is being urged to contact the force via their website and should quote incident number 312 of 23 October.