Yobs hurling stones at moving traffic from a motorway bridge in Bedfordshire were caught on camera in a CCTV image released by police.
Three youths threw the missiles, which smashed the windscreen of a Post Office lorry, sending broken glass flying into the driver's eye.
The incident on June 12, which happened at about 8.40pm near the Luton Rugby Club at Slip End Road is one of eight recent occasions on which rocks or stones were thrown from bridges on to moving traffic on the M1.
Three drivers have received medical treatment after glass fragments hurtled into their eyes and the volleys have caused expensive damage, Bedfordshire Police said. In one incident, an ambulance windscreen was smashed at one of the Luton motorway bridges.
This was one of five cases reported in a half hour period between 7.40pm and 8.15pm on June 8. Detectives are trawling through other incidents that may be linked, including two lorry drivers who were targeted on May 19. Again, one reported getting glass in his eye.
The three youths involved in the latest incident are described as being white boys aged between about 13 and 15-years-old, all wearing hoodies. One was described as having ginger hair.
PC Charlie Pirie, investigating, said: "It goes without saying how dangerous these incidents are.
"There has been expensive damage caused to the vehicles involved and three drivers have needed medical treatments for glass fragments in the eye, but fortunately none of the injuries have been serious.
"However, it doesn't take much to imagine what could have happened if one of these heavy goods vehicle drivers had lost control of his lorry.
"Other road users would have been at extreme risk of being involved in a high speed collision and terrible consequences could have followed."