Have you ever driven somewhere and can't remember details of the actual drive, like billboard signs or red lights at major intersections? If you've ever had this experience, chances are you were daydreaming or "lost in thought" while driving.

Daydreaming is the No. 1 driving distraction in fatal crashes in the United States, according to an Erie Insurance analysis of National Highway Traffic Safety Administration (NHTSA) data.

Erie analyzed data from NHTSA's Fatality Analysis Reporting System, which includes police reporting from fatal car accidents. Erie found that between 2013 and 2017, the days with the most fatal accidents caused by daydreaming were Saturdays in September.

Top 5 days/months for daydreaming causing fatal accidents:

  1. Saturdays in September
  2. Saturdays in May
  3. Fridays in October
  4. Saturdays in August
  5. Fridays in July

Bottom 5 days/months for daydreaming causing fatal accidents:

  1. Tuesdays in February
  2. Wednesdays in February
  3. Mondays in January
  4. Thursdays in February
  5. Sundays in December

Erie Insurance previously collaborated with Paul Atchley, a cognitive behavioral researcher who studies distracted driving. To combat daydreaming while driving, Atchley recommends doing a passive task, like listening to the radio or talking with a passenger. Passive tasks can be tuned out when you need to focus on heavy traffic and road hazards.

We know that talking on a cell phone is distracting. Atchley explains that a phone-conversation mate doesn't have the same risk as someone sitting in the passenger seat and they can't see any upcoming road problems. That means the person on the other end of the phone will keep on talking when traffic gets heavy.

Distracted driving accounted for 3,166 deaths, or 8.5% of all fatal car crashes, in 2017, according to NHTSA.