The M62 has been closed after children were seen playing on the motorway.
Highways England says staff in its CCTV control centre have witnessed youngsters running across all four lanes near junction 27 at Birstall in the past few minutes.
Traffic officials have published a picture of two children leaning against a barrier under a motorway bridge.
At about 8pm it said traffic was being held in both directions until they can be found and taken away to safety.
Queues quickly built up as the closure is at one of the busiest spots on the M62, close to the turnings for the M621 and the M1.
The motorway was re-opened at 8.20pm.
Highways England commented: “The children have now left the network.
“Years ago your mum used to tell you ‘go play on the motorway’.
“It was never a wise saying. We hope kids stay on the real playground.”
The motorway is being closely monitored for the rest of the evening in case the youngsters return.
