PC Martin Willis spotted the overturned Iveco van on a bridge at junction 44 near Bramham, above the A64, shortly before 6am on December 1.
“Vehicles were going past and it was quite windy so the vehicle was actually rocking and I’m thinking this could go over onto the A64," he said.
"It’s about a 40ft drop and it’s going to kill the driver and people travelling underneath as well.
“I thought the only thing I can do is try and steady it. I said to the driver, ‘whatever you do, don’t move’.
After PC Willis came to the rescue, firefighters spent two hours making the van safe and freeing driver Thomas Dulson.
The 25-year-old was then rushed to Leeds General Infirmary with two broken legs.
Today West Yorkshire Fire Service released two clips showing the arrival of fire crews and the work they carried out alongside colleagues from Yorkshire Ambulance Service's Hazardous Area Response Team.