(NEW YORK) -- Thanksgiving was the deadliest holiday in 2010, according to the most recent data available from the National Highway Traffic Safety Administration.
That year, 431 people died on the roads nationwide, compared with 259 on Christmas, 403 on Labor Day and 392 on Fourth of July.
"Whenever you increase the number of people traveling, and the number of cars, your likelihood and chance of having an accident are going to increase just by statistics," said Dr. Rahul Sharma, who heads NYU Langone Medical Center's Emergency Department and has worked his fair share of holidays in the ER.
An estimated 90 percent of Thanksgiving travelers will drive to their destinations this Thursday, according to the AAA auto club. That's 39.1 million people on the roads.
Sharma said car accident injuries can vary depending on what time the accident happens. During the day, when roads are gridlocked, collisions happen at lower speeds and result in more minor injuries, including bruises and neck injuries.
"If there were to be a silver lining, that would be it," said Jake Nelson, AAA's Director of Traffic Safety Advocacy and Research. "I'm not sure anyone would pray for congestion though."
Late at night, however, ER doctors start seeing more serious injuries as travelers are able to go faster on the emptying roads, Sharma said. The holiday alcohol and distracting family drama can also contribute to slower reaction times.
And as it gets later, more impaired drivers get behind the wheel, said Dr. Curt Dill, who also works in the NYU emergency room. He said that 11 p.m. to 4 a.m. are normally the worst hours, but by 2 a.m. on Thanksgiving, drivers might be traveling so fast that they look like they're "drag racing," causing cars to lose control and even flip over.
Dill said injuries depend on whether drivers are wearing their seat belts and how fast they're speeding.
"If you're wearing a seat belt and driving a modern vehicle with restraints on, then lots of collisions are survivable," he said. "But if you're not wearing your seat belt, you're crashing into a several-ton piece of metal."
That means, broken bones, internal bleeding, head injuries and even death.
Copyright 2012 ABC News Radio