The M1 closed completely in both directions between junction 41 (Carrgate) and junction 40 (Ossett / Wakefield) in just under three hours.
A West Yorkshire police spokesman said officers were called in to report security concerns for a man on the highway to the south.
They said the man was believed to have fallen from a height. It is believed to have been from a bridge over the main highway.
Severely wounded.
The man was rushed to the hospital by ambulance, which was found landing at the scene around 15.45.
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The incident was initially reported at 1.51pm, according to AA.
The closure caused traffic back at junction 42 (Lofthouse) on the southbound highway and junction 39 (Wakefield) on the northbound freeway.
The north M1 motorway at junction 40 (Ossett / Wakefield). Image: National Highways: Yorkshire
The vehicles caught in the closure were waiting for instructions from the National Highways: Yorkshire officers and police at the scene.
A spokesman for National Highways: Yorkshire said at 3:26 p.m.
“They will get you out of the closure as soon as possible.”
The northern highway of M1 between junction 40 and junction 41 reopened at 4.30 pm.
But the southbound highway is still closed and will be for a long time.
Traffic within this block will be released soon.
A full statement from West Yorkshire Police said: “At 2.47pm, police were called in to report security concerns of a man on the M1 motorway heading south to Wakefield.
“It is alleged that he suffered serious injuries after falling from a height.
“He was taken to the hospital for further treatment.
“Investigations are ongoing and the roads remain closed at this time.”
