The family of a man who died Saturday after falling out of a party bus as it drove on an interstate highway has filed a lawsuit against two suburban transportation companies.

Kimberly Larsen filed the suit on behalf of her son, James “Jimmy” Larsen, against VIP Charter Inc. and Select Limousine Inc. on Thursday in Cook County Circuit Court.

Larsen was a passenger on a 2012 Freightliner bus about 3:05 a.m. Saturday on Interstate 294 near Lake-Cook Road in Deerfield, according to Illinois State Police.

Larsen walked toward the front of the bus to adjust the radio when the bus “negotiated the bend on I-294 near Lake-Cook Road in such a manner that caused Jimmy to stumble and fall down the stairs leading to the exit door,” according to the suit and state police.

Larsen subsequently fell out of the door and onto I-294, where he was struck by a black SUV. The Libertyville resident was pronounced dead at the scene of multiple blunt force injuries, police and the Cook County medical examiner’s office said.

“It was a freak accident,” Zahair Nubani, an attorney representing Select Limousine said. “It was a tragedy, but not negligence on our part.”

Nubani said the bus had been inspected by the state a few weeks before the accident.

According to the suit, both VIP and Select are listed as registrants for the bus’ license plate by the State of Illinois.

“We don’t own the vehicle or [have] anything to do with the driver or accident,” a spokesperson for VIP said when contacted through its Facebook page.

Reached by phone, Garbriel Tataru, owner of Select Limousine, said he owned the party and had not yet taken VIP Charter’s logos off after taking back possession of the vehicle from VIP when they failed to make two lease payments.

Both companies were negligent when they failed to prevent the doors of the bus from opening while it was moving, the suit alleges. Additionally, the companies did not ensure passenger safety when they required passengers to manually operate the music system near the stairs and exit door.

The suit seeks $50,000 in damages from each company.