Forty-four people were on board the Arrowhead Coach USA bus, which was traveling from Niagara Falls to Waterbury, Conn. when it crashed Sunday on the New York State Thruway, 16 miles south of Rochester. Two other vehicles also wrecked.
The driver, who did not appear seriously hurt, indicated he had a diabetic condition, which may have played a part in the accident, state police Maj. Mark Fischer said.
Before the crash, several passengers tried to warn the driver to pull over but he did not, Fischer said. Some passengers said it appeared the driver fell asleep.
"He was just dozing off," Migdalia Asevedo said. "A lady in the back of the bus was yelling at him for falling asleep."
Said passenger Angelo Serano: "We screamed and he realized (he was going to crash), but he already lost control."
Trooper Robert Barrett said the driver was properly registered and slept eight hours the night before the accident.
No charges have been filed against the driver.
The five dead were found in the center of the bus and all were ejected or partially ejected, Fischer said.
The identities of the victims were not immediately released.
Twenty-three people were transported to Strong Memorial Hospital in nearby Rochester. They ranged in age from 11 months to 60 years old; seven were younger than 16.
Four were critically injured but were expected to survive, and an 18-month-old child suffered a blow to the chest but was expected to recover, Fischer said.
A minivan caught in the accident overturned and another car was hit by a guardrail that broke free after the bus slammed into it. Passengers in those vehicles reportedly suffered only minor injuries.
"It made a royal mess," Trooper Gary Link said. "It's one of the worst accidents I've seen and I've been here 11 years."
Coach USA had no immediate comment.