There are usually more fatal car accidents on holiday weekends than in typical three-day periods, according to studies like those by the National Highway Traffic Safety Administration (NHTSA).
Some of the deadliest holidays are Memorial Day, Labor Day, and the Fourth of July. Even Martin Luther King Jr. Day and Presidents Day weekends experience a higher than average number of fatal crashes.
A primary cause of the increase is that people often drink more than usual over the holidays, plus there are typically more people on the road around these celebrations.