Witnesses spotted a group of young teenagers in the area at the time
Five drivers said their vehicle was hit by stones between junction 27 and junction 28 from 11.15pm on Monday, 17 August until 9.55pm on Tuesday, 18 August.
Damage was done to all five vehicle’s windscreens, two of which were HGVs.
A group of people, aged in their early teens,were spotted in the area at the time.
Detectives are working to find those involved.
“Fortunately, no one was injured but the actions of the people involved put motorists at serious risk of harm,” said Chief Inspector Darren Deex.
“I understand that some children, possibly in their early teens, were seen on the bridge.
“I urge parents and guardians to help educate your children or young people in your home about the consequences of their actions for them and for innocent motorists.
“If you live nearby, please ask yourself, do you know what your children are up to? Could they be their friends be involved in this behaviour?”
Anyone with information is asked to contact police on 101 or by visiting their website here.
Alternatively, you can call Crimestoppers anonymously on 0800 555 111.
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