The Forth Road Bridge has reopened after interim repairs were completed ahead of schedule.
Traffic was back on the bridge from before 6am, according to a spokeswoman at Transport Scotland.
It was due to reopen from 6am to all vehicles except HGVs, which are not expected to be given access until mid-February.
It was previously announced the bridge, which links Edinburgh to Fife, would be closed until the new year.
Scotland's transport minister Derek Mackay said: "I am pleased that we are now able to reopen the bridge to 90% of traffic, well ahead of schedule.
"Following rigorous testing and inspection of the temporary repair, experts have recommended the bridge is now ready to open to all traffic except HGVs."
Ministers were forced to close the 51-year-old bridge to all traffic on December 4 after a crack was found in a truss end link during a routine inspection.
A steel splint has been put in to repair the damaged part, with similar splints to be installed at the other seven truss end links as a precautionary measure - work which can be done safely while the bridge is open.
Load testing of the bridge following the interim repair work showed it can now be safely opened to all vehicles except HGVs.
They will not be allowed back onto the bridge until the permanent repair work is in place.
This is expected to take about six weeks to complete, depending on the weather and no further defects being found.
Ministers said they will discuss with hauliers the operational support that can be offered to them during the period when they cannot access the bridge.
Officials said a full inspection of the bridge was 90% complete "with no material defects detected". Remaining inspections will continue until early January and can be safely completed while it is open.
The bridge is used by an estimated 70,000 vehicles a day, with its closure causing significant disruption to commuters and businesses.