Study: What Kind of Germs are Living in Your Car?

Germs in Your Car

Germiest Surfaces in Your Vehicle

Ah, the freedom of the open road. Tunes on the radio, wind in your hair, and billions of germs at your fingertips—wait, what? That’s right, your car is a breeding ground for all sorts of bacteria and fungi. Some are harmless, while others can make you seriously ill. 

Nowadays, many of us are more concerned than usual about the spread of germs and getting sick. Car interiors are often an overlooked space that need regular sanitizing to be safe for you and your passengers. We recently swabbed some cars of people with and without kids to see which high-touch areas were the germiest. Here’s a look at our findings and some helpful tips for keeping your car clean.

Key Findings

  • Steering wheels have 24% more bacteria than a toilet handle.
  • Car air vents were one of the cleanest parts of the car, with less than half that of a keyboard.
  • Car owners with kids were likely to drive a car 60% germier than a car owner without kids.

Where Germs Lurk in Your Car

People spend a lot of time in their cars, especially when they need to travel for work, errands, or the holidays. It’s estimated that the average American drives about 25 miles a day, which equates to around seven hours in the car each week. Of course, these numbers vary depending on different lifestyles, but no matter how often we’re in our cars, we can all benefit from knowing which surfaces need the most attention.

Infographic: germiest interior car surfaces

Our research determined that the steering wheel can be the germiest high-touch surface in a car, followed by the driver’s interior door handle. These areas are dirtier than a remote control, computer keyboard, and toilet handle. The back seat, where kids and pets most often spend their time, was surprisingly much less germy. Air vents were the cleanest surface of all that we tested.

Do Kids Make Cars Germier?

Our study revealed that yes, on average, kids do make cars germier. When comparing vehicles, we found that a car owner with kids is likely to drive a car that’s 60% germier than a car owner without children.

Infographic: germiest car owners

Spilled food and drinks, spit-up, diapers—there are many factors that can cause higher numbers of bacteria and fungi in cars with kids. Regularly wiping down high-touch back-seat surfaces, plus washing and sanitizing car seat covers, belts, and buckles can help keep things healthier.

The one major exception we noticed between these two types of car owners was the bacteria count on their steering wheel. Car owners without kids had steering wheels that were 96% dirtier than drivers with kids (270 CFU/10 sq. cm vs. 10 CFU/10 sq. cm). Child caregivers are likely well aware of the germiness of kids, so perhaps they’re better at regularly sanitizing their own hands before grabbing the wheel.

Harmful Bacteria Breakdown

The swab samples we took from each surface showed three types of bacteria: gram-positive cocci, gram-negative rods, and bacillus. Most are harmful and could cause infection once they enter the body through the eyes, nose, skin, or mouth. Bacteria that lead to issues such as strep throat, pneumonia, and gastrointestinal discomfort were all present in our samples.

Infographic: most common bacteria types found in cars

Stay Safe in Your Car and on the Road

Luckily, there are steps you can take to protect yourself and others from harmful bacteria and viruses in your car. Sanitizing hands before entering the car is a great way to reduce how much bacteria you’re introducing into the space. Outlawing food and drinks in the car can also help, as does placing items in the trunk instead of on seats.

Regularly vacuuming, dusting, and wiping down high-touch areas with sanitizing wipes or sprays (while wearing gloves) is the best way to keep it clean. And don’t forget touch screens, knobs, handles, and cup holders. We also encourage drivers to protect themselves on the road with auto insurance. Get a free car insurance quote and find the best coverage for your vehicle today.

Methodology and Limitations

We conducted 12 total gram and stain culture swab tests from four different items or surfaces in a vehicle. Each surface was swabbed three times from two different vehicles. Colony-forming units per swab were averaged for each surface type. It is possible that with a larger sample size of surfaces, we could have gained more insight into CFU levels. No statistical testing was performed, and the claims listed above are based on means alone. As such, this content is exploratory.

Fair Use Statement

Excited to tell others about our germy car study findings? Feel free to share our project for any noncommercial use, but please remember to link back to this article as a credit to our creative team’s hard work.

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