A woman and two men were seen throwing the items from a bridge above the A20, just before junction 3 on the M25 near Swanley.
The incident happened between 6.05pm and 6.15pm on Friday 2 April 2021 and one vehicle, driven by a woman, was struck. This resulted in the windscreen breaking and the victim being covered in glass.
Investigating officer, PC Reece Watkins of the Sevenoaks Local Policing Team, said: ‘Throwing items from heights towards oncoming vehicles is extremely dangerous and it is only sheer luck that the victim was not seriously hurt.
‘We have been making enquiries in the area to identify the suspects and I am appealing for anyone with information or dashcam footage that may assist the investigation, to contact us.’
Anybody with information is urged to call Kent Police on 01622 604100, quoting crime reference number 46/54130/21.
You can also contact the independent charity Crimestoppers, anonymously, on 0800 555111 or by using the online form on their website.