NASHVILLE (AP) — The holiday season is one of the most dangerous times of the year for motorists due to an increase in impaired driving. That's why Tennessee state troopers will be stepping up enforcement over the Christmas holidays.

According to the Tennessee Department of Safety and Homeland Security troopers, the increased enforcement begins just after midnight on Friday and runs through midnight on Tuesday, Dec. 25. It includes saturation patrols, bar and tavern checks, and driver license and sobriety checkpoints.

The Safety Department suggests that designating a sober driver and not letting friends drive drunk are simple ways to avoid a tragic crash or an arrest for impaired driving.

During the 2011 Christmas holiday, nine people were killed on Tennessee roadways in six fatal crashes.