Police have also made an arrest after they were called to the incident on the motorway near Chapelhall in North Lanarkshire at rush hour this morning.
They say they arrived at 8.55am following the incident on the slip road at Junction 6.
But the man had left the scene on foot prior to their rivals.
Officers have described the incident as targeted.
The road was closed as cops combed the area and a firearm was found. It has been recovered.
A 35-year-old man was subsequently traced and has been arrested. Enquiries are ongoing.
The M8 slip road and part on the A8 eastbound at Eurocentral were closed for around seven hours while enquiries were carried out. The road has since fully reopened.
Detective Inspector Stephanie Bertram, of Lanarkshire CID, said: “We believe this was a targeted incident and we are following a positive line of enquiry.
“The M8 would have been busy at the time and I would ask any drivers with dash-cams to please check their footage and contact us.
“I am also keen to speak to anyone who may have any information surrounding the circumstances of the incident as it is vital that we find out exactly what has happened.
“Officers have already spoken to some motorists who stopped at the time of the incident and I would like to thank everyone for their help so far.
“I would urgently appeal to anyone who was in the area, and who has not already spoken with us, to please do so.”
Chief Inspector Gail Nicol, local area commander, said: “We understand this incident may be worrying for the local community and I would ask anyone with any concerns to speak to us.”
Anyone with information can speak to officers, contact Police Scotland via 101 or call Crimestoppers on 0800 555 111, quoting incident number 0602 of Monday, 3 February, 2025.
