It’s easy to fall into the trap of thinking that a quick wash of your car’s exterior is enough for it to be considered “clean.” But consider this – where do you spend most of your time with your car? Not standing around outside it (unless you enjoy admiring your car). You spend most of your time driving it, and it’s the interior that’s your biggest challenge when it comes to dirt and grime.
You don’t have to take our word for it either. In 2022, researchers at the U.K.’s Aston University carried out a study to figure out where the most bacteria grow in cars. The study showed us the five dirtiest places in your car, minus the gearstick because cars with manual transmissions accounted for just 1.7% of car sales in the U.S. in 2023.
1. Your Trunk
Think about the sorts of things you might keep in your car’s trunk and it’s obvious why this place tops the list when it comes to the most dirtiest places in your car. Spare tires, tools, jacks, and similar practical items are important. However, all these items also get dirty when used, making it breeding grounds for bacteria. Add a lack of vacuuming and cleaning to the equation – it's no wonder car lovers turn to deep car cleaning services.
In fact, it’s dirty enough to be home to 1,425 types of bacteria according to the Aston University study. Now, what do you also put in your car’s trunk beyond the practical and dirty stuff? Groceries, perhaps? All of that bacteria in your trunk can easily spread to food – especially loose foot items – making every 20-minute trip to the grocery store a hazard.
2. Your Driver’s Seat
It may be where you park your rear-end every time you drive, but it’s not always your own body that you have to worry about when it comes to making your driver’s seat dirty. It’s what you do in that seat that counts. Over half of Americans (56.7%) say they eat and drink while driving regularly. That’s over half of car owners spilling liquids and dropping crumbs all over their driver’s seats.
Keep that statistic in mind and it gets easier to see why your driver’s seat can become so dirty. The Aston University study confirms it – the researchers identified 649 types of bacteria on the driver’s seats they examined.
3. Your Back Seats
The same dirt-spreading practices that apply to your driver’s seat also apply to your car’s rear seating area. Only, the bacteria problem isn’t quite as bad – “just” 323 were identified in the study compared to 649 found on drivers’ seats. It’s likely this is due to your back seats being less used than your driver’s seat. Somebody will always be in the latter when the car is in use, but you’re not always carrying passengers.
However, many people use their back seats like makeshift trunks when they have no passengers. How often have you dropped a few bags of groceries on those seats when the trunk is full? Maybe you’ve thrown a jacket back there, one that has dirt and debris on it from whatever you were doing outside. These things, which we often do without thinking, all contribute to bacteria being spread into the seats your passengers (or perhaps even your children) use.
4. Your Dashboard
Take a look at your dashboard and you’ll see a large and mostly flat surface, though with plenty of knobs and little crevices. That alone makes dashboards the perfect place for dust and other grime to accumulate. Now think about what you often do with your dashboard.
Touch it with your hands.
Every flick of a switch and turn of a knob creates a two-way path of dirtiness challenge in your car. There’s the path from you to the dashboard. Whatever was on your fingers gets spread onto the knobs and switches you fiddle with on your dash. And, of course, this path goes the other way as well – whatever was on the dash moves onto your fingers. As for what precisely could be on your dashboard, the Aston University study says up to 317 different types of bacteria.
5. Your Steering Wheel
We have some conflicting numbers when it comes to your car’s steering wheel. Aston University identified 146 types of bacteria on the steering wheel during their study, placing the location sixth in the overall list of dirtiest places in your car (fifth when discounting the gearstick your car probably doesn’t have). However, a study conducted over a decade before suggests your steering wheel could be even dirtier than that. Researchers from London’s Queen Mary University found that there may be as many as 700 germs per square inch of your steering wheel.
That’s about nine times as many as you’d find on the average public toilet seat, according to the researchers.
Even if the lower number is more accurate, that’s still a lot of bacteria being transmitted to your fingers whenever you drive. If you’re not cleaning your steering wheel regularly, you also have bacteria moving from your hands onto the wheel. It multiplies and you get a nasty transmission cycle.
Conquer the Dirt in Your Car
There’s something we haven’t told you about the Aston University study:
The types of bacteria that fester away in the dirtiest parts of your car include Staphylococcus Aureus – a bacteria linked to MRSA – and Pseudomonas, which can lead to infections that are tough to treat with antibiotics. Eliminating the dirt is your priority when you have such microscopic nasties in your car. Professional car detailing companies in Gilbert AZ can handle the problem because you get a comprehensive clean that covers all of these five areas, along with the rest of your vehicle.
