The M8 was closed in both directions due to a police incident.
Police and emergency services were called out at 6.55am to a man on an overhead bridge on the M8 westbound near Baird Street, Glasgow.
Traffic Scotland has confirmed the road has now been reopened but traffic “remains heavy”.
A spokesman for Traffic Scotland said: “The M8 has reopened east and west at J15 following an earlier police incident.
“Traffic remains heavy and will take some time to clear, so do expect further delays.”
The Great Scottish Run is being held in Glasgow today, and runners faced delays in start times.
A spokesman for Police Scotland said: “Police and emergency services were called at 6.55am on Sunday morning after a man threatened to jump from an overhead bridge on the M8 westbound near Baird Street, Glasgow.
“Emergency services are still at the scene. Police negotiators are trying to coax the man down safely.
“The M8 is closed in both directions at junction 15/16. Diversions are in place and police advising people to avoid the area until further notice.”