National Highways Yorkshire closed lanes one and two of the A1 southbound at Junction 34 Hook Moor at about 4.15pm.
This was due to a vehicle fire.
At about 5.10pm, all lane closures were removed.
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Traffic is now flowing in all three lanes, but Highways England warned that there are still delays of around 15 to 20 minutes.
The AA said average speed on the A1 between Boston Spa towards Lotherton is around 30 mph.
In a separate incident, The AA has also reported delays in Harewood.
It said: "Severe delays of 14 minutes and delays increasing on A659 The Avenue Westbound between Moor Lane and A61 Harrogate Road.
"Average speed five mph."