Seventeen people are in hospital after a minibus carrying football supporters crashed on the A1M near Pontefract.
Police said the collision, which happened at around 19:00 BST on Saturday, involved a black Skoda Fabia and an Iris single-decker minibus.
The minibus was carrying South Shields FC fans with seven of the casualties thought to have suffered serious injuries.
The club’s sporting director said it was “an absolutely horrific incident”.
Lee Picton said when he first heard what had happened he felt “sick to my stomach, not knowing exactly what has happened.
“The only saving grace, touch wood, is that nobody has life-threatening injuries as far as we’re aware.”
Mr Picton said he understood the minibus had “rolled over a number of times when it’s tried to avoid colliding with another vehicle”.
He said the incident had been “really traumatic” for those involved.
“We’ll be doing everything we can as a club to contact those people personally to see how they are and offer our support,” he added.
The South Shields fans were travelling back following a 3-2 defeat against Tamworth, in the penultimate match of the Vanarama National League North season at the Staffordshire club’s Lamb Ground.
Mr Picton said from phone conversations he had made about the crash he had learnt of the “unbelievable effort other fans who weren’t involved in the incident made”.
“They’ve travelled to the crash site to offer their support and comfort to the people who have been involved,” he said.
“So I just want to thank, on behalf of the club, all of those fans and others who stopped at the roadside to assist people in the accident,” he added.