"There is a zero-tolerance campaign in effect on Interstate 80 during the holiday period that extends from San Francisco down to the Nevada state line, all the highway patrols areas are stepping up enforcement," says Officer Steve Skeen with the California Highway Patrol.
Zero-tolerance means the troopers could stop you for speeding, DUI checks or just make sure everyone is buckled up.
He says summer holidays at the lake overcrowd the area, adding to the congestion caused by narrow and winding mountain roads.
"My biggest concern is people giving enough stopping distance between one another. Certainly, you can turn a corner up here and traffic could be stopped and if you're not looking down the road or paying attention, then subsequently, you too could be a victim of a traffic collision."
According to the National Highway Traffic Safety Administration says almost 55 percent of all traffic deaths on the fourth involve alcohol.
The troopers say mixing alcohol on these roads has proved to be deadly.
"Unfortunately, I've worked and investigated several very bad accidents involving DUI drivers. There's not much room to go on these roadways up here and there's areas where a cross-over type collision results in a head-on type collision which are the worst."
Troopers also warn about driving during the early morning or late night, deer and even bear have been known to dart out in front of the road.