A TV presenter has said it was lucky "nobody was killed" after a rock was thrown from a motorway bridge, striking her sister's car.
Gina Bradbury Fox, sister of former Countryfile host Julia Bradbury, was driving from London to Sheffield on Saturday when her car was hit on the M1 in Nottinghamshire.
Ms Bradbury Fox said the incident "would have been catastrophic" had she not stayed in her lane.
Police said they were investigating.
Ms Bradbury Fox, 60, said she "saw this thing coming through the air" while she was driving with her friend on a work journey.
"It hit the bonnet then bounced up on to the windscreen, which cracked," she said.
Yesterday my sister was travelling for work along the M1 between junction 26 & 27 in Nottinghamshire when 3 young'uns threw a huge rock down onto motorway. It hit the bonnet & smashed the windscreen.She careered off the road avoiding cars but luckily nobody killed...— Julia Bradbury💙 (@JuliaBradbury) April 11, 2021
"It was big enough to see it coming through the air, and I couldn't go anywhere - if I had moved into a different lane or the barrier that would have been catastrophic.
"I pulled into the hard shoulder. My mate was shaking."
'Shocking and frightening'
After the incident Ms Bradbury Fox said she saw "three youngsters running off the bridge", and said she would "like to turn this into a positive" by meeting them.
"I'm actually very sad that kids have not got enough to do in their communities to keep them busy [and] they have to go and do something like that," she said.
"If their mother or father or sister or friend was sitting in a car and was killed as a result of someone chucking a rock over the bridge, how would they feel?"
After the incident, her sister tweeted, saying "luckily nobody was killed" and called on anyone with information to contact the police.
Nottinghamshire Police said officers have reviewed footage of the item - which is "believed to be a stone or a rock" - and would like to speak to three young men seen near the footbridge in Hucknall.
Insp Mark Dickson said: "This was a reckless and dangerous act that put multiple lives at risk.
"It was only a matter of good fortune this object hit the bonnet first before it hit the windscreen.
"Luckily the driver was not injured, but it was a shocking and frightening incident that could have been an awful lot worse."