Caltrans Reminds Motorists of Safe Driving Tips for Foggy Conditions


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Date: December 22, 2022  #22-177

District: District 3 - Marysville,

Contact: Gilbert Mohtes-Chan                                                                     

Phone:(530) 682-6145


Marysville — Motorists are reminded to plan for extra travel time and remember safe driving tips for foggy conditions this holiday season.

The National Weather Service is predicting areas of dense fog through this week and the long holiday weekend in the Sacramento Valley and northern portions of the San Joaquin Valley. Motorists may experience travel delays at times because of low visibility.

Two cars driving through fog visibility

Throughout the fall, winter and early spring, the Central Valley often finds itself shrouded in thick ground fog, better known as Tule fog, which emerges after rains saturate the soil.

Nearly three in four fog-related traffic collisions are connected to motorists driving too fast, statistics indicate. These collisions also result in the highest fatality rates.

To help motorists navigate safely through foggy conditions, Caltrans offers these driving tips:

  • Reduce your speed to ensure a safe stopping distance.
  • Drive with headlights on low beam. Never drive with only the parking lights or fog lights on and avoid using high beams in fog.
  • Use extra caution when crossing traffic or busy intersections, especially in dense fog. Lower your window and listen for traffic you can't see.
  • Use windshield wipers and your defroster to improve visibility.
  • Be patient and don't pass long lines of traffic.
  • Use the “fog line” on your right shoulder as a guide.
  • Avoid stopping along the freeway or highway shoulders.

When looking to exit, the solid white line on the shoulder will veer to the right, breaks for a few feet and then resumes along the ramp. Also, highways prone to fog will have markers that follow a 3-2-1 dot countdown pattern to let motorists know there is an exit ahead. On the right shoulder, drivers will see three reflective markers 2,100 feet before the exit, two markers at 1,400 feet and one marker at 700 feet.

District 3 is responsible for maintaining and operating 4,385 lane miles in 11 Sacramento Valley and Northern Sierra counties. Check out Caltrans' QuickMap for current road conditions and chain requirements at or download the free QuickMap app on the App Store or Google Play. Motorists also can call the California Highway Information Network automated phone service at 1-800-427-ROAD (7623).

Fog foremast information