(Harrisburg) -- With Thanksgiving the most dangerous holiday for travelers, Penn DOT is partnering with police to encourage safe driving. Penn DOT says motorists should expect heightened enforcement of seatbelt laws and be aware law enforcement will be on the lookout aggressive and impaired driving. There will be sobriety checkpoints as well as regular traffic safety patrols. Penn DOT spokeswoman Erin Waters advises drivers who find themselves in bad weather and heavy traffic: cool your jets. "If you’re on the road and either the weather is inclement or maybe you’re stuck in traffic, try to keep calm, a lot of people are on the road with you, and always increase your following distance," she says. "If you’re on slushy or snowy roads, or even if there’s rain, you know, give yourself time to react." Some 4,000 traffic accidents occurred during last year’s Thanksgiving holiday travel period. That’s more than twice as many crashes recorded during the Christmas and New Year’s holiday weeks combined.